Huge Relationship Dillema

I am 23 and have been with my girlfriend for 4 years now (she is my first official girlfriend I have ever had). The biggest reason, I believe, that we have remained together this whole time has been companionship: we like to go to new places together all the time and explore fun new restaurants, malls, etc. together. Basically, we are like best friends, are physically attracted to one another, have very close communication with each other (open about everything), and both enjoy each others presence in public as well, considering the fact that we are both fairly good-looking individuals. Now aside from the Romeo and Juliet lifestyle described above, there are some personality traits that she possesses that have bothered me since I first met her. For example, I see the following insecurities in her:

1. If there is a mirror, she will check herself out in it 100000000 times (not sure if that's normal or if all girls are like that). She is SO obsessed with her looks!
2. Everytime we go out and meet a new couple, once the event is over and we are driving back, she will CERTAINLY start to say something negative about the girl (such as, "Well they were a pretty cool couple, but I don't know, Megan is a very weird girl, she's so...". This makes me think she is insecure about herself and wants to eliminate potential competition by trying to make me think badly about all girls around us. In general, she will whine, complain, and put things down around her all the time.
3. She loves attention! Okay, I know they say all girls love attention (and this is also true for many guys as well), but at parties or social gatherings, she LOVES to talk a lot and be the center of attention (and she even speaks in an above-average high volume, as if to ensure her voice will be heard above all).
4. In general, maybe 90% of the conversations she holds are all about "I, I, I, me, myself, ..." It gets to a point that I just get SUPER annoyed. In front of others, she is not humble AT ALL and will say things like "I am so smart...," "I have always been good at...," and other cocky, non-humble statements. I have told her this before, and she justifies it with "no, it's not that bad, in this world you have to sell yourself so they don't think badly about you." If it's a job interview, I understand, but for everyday social gatherings, I don't buy that. I hate how she tries to prove her worth to everyone.
5. In public, she laughs alot (I don't mean at jokes), but even at unnecessary times (the way people do when they are uncomfortable or insecure and are desperate to fit in).
6. She tries to be too friendly with new guys that she meets and in my opinion crosses the line such that they feel comfortable to start flirting with her or talking to her inappropriately (she makes it almost too easy for them, then turns around and rubs the situation in my face). To top it all off, she then comes to me and explains with a big smile what happened and how a guy at work was trying to flirt with her, etc. WHY WOULD YOU TELL YOUR BOYFRIEND THIS? Besides the fact that yes, I do get a little bit jealous hearing all about that, what disgusts me even more is how she is insecure and always has this urge to share stories like this (or perhaps sometimes even make some up) to perhaps prove to me that she is very likeable (even though I ALWAYS treat her with utmost respect and never make her feel unwanted).

Earlier, I did mention that we have a great open/honest communication with each other. Because of this, I have talked to her about each and every single bullet point mentioned above and told her how I despise each of them. For all of them, she agreed 100% and said okay, it won't happen again, but it all continues to happen. Seeing how this cycle happens again and again, I am not sure: am I just being too picky and stressing out about pointless things, or are these real concerns that I should be aware of? The last thing I want is to live a stressfull life by being stuck with a wrong girl who confuses me by frequently saying "I LOVE YOU SO MUCH!"

Please, any honest opinion/guidance you guys can give me, I will greatly appreciate it. Don't hold back on any thoughts!

Thanks...

She sounds very insecure to me.

All the flags are there :

. girls putting other girls down all the time..huge flag.
. If she knows she looks good she does not need to remind it to herself about a million time every day.
. laughing inappropriately to draw attention to herself.
. overtly flaunting herself when there is no need to. Nothing put others off like posers who think they are soo better than anybody else. I have known people like that : words words words..prove it with action !
. attention seeker..other men..no boundaries..no awareness of what is appropriate or not : she is selling herself short actually !
. showing disrespect towards you. somebody who is confident does not seek attention from other men and then flaunts it to your face.
.nobody is perfect and somebody a bit more humble would be actually more attractive.

well does she have any girlfriends ?

I do not know her, her hobbies or anything..but by this resume..

she would be a major turn off to most guys actually. I mean serious and OK ones.

My point of view..based on what you wrote.

First of all, thank you very much for taking the time to read my post and responding! Secondly, thanks for your honest opinion.<br />

To answer your questions:

• Girlfriends: She doesn't have any close girlfriends, though she does have about 5 friends she's had since childhood, so once in a blue moon, they will all go out together. She has, at one point or another, shared some negative views about every single one of them, and most of them are single girls without boyfriends (and she always badmouths her cousins behind their backs as well, all of which are female). About her friends, she will always say something like "they are jealous of me" and are "so weird." About cousins, she always says things like, "Oh my God, they are SUCH showoffs!"...but then I see her do some of those same showoffy things at times as well.
• Hobbies: She has a newfound hobby (about a year old), which has to do with collecting antique tableware. Lately, she found a way to turn it into a business, and in front of public, will almost ALWAYS voluntarily start talking about her business regardless of who the audience is.

So seeing how she is so insecure, honestly, what would be the best action for me take? Is this insecurity something that will always cause problems in our marriage in the future, or is it something I should get myself used to? I'm very confused at this point of the relationship.

would you want her to be the mother of your children?

Nope.

"Seeing how this cycle happens again and again, I am not sure: am I just being too picky and stressing out about pointless things, or are these real concerns that I should be aware of"

Well .. I was going to say that you two have already been in a relationship for 4 years now. And it seems like you know a lot about her. But here's the thing: shouldn't you love your girlfriend for who she is? Sorry to say this, but if you really dislike her so much or are complaining about her so much, maybe she isn't the right one
That's just my opinion.

i'm 23 and single now. so it makes me sick when i hear about guys who are with girls like that...idk dude. i've been dumped bc of my mental problems (borderline/bipolar) but i've never done stuff like that. so it just makes me wonder if being vain/mean/pretentious is better than being sensitive/passionate/genuine (i.e. ME).

but goodluck in whatever you decide. in the words of Sylvia plath "if you love her, you will love somebody else someday"

I think because this is your "first official girlfriend" it might be hard to realize the relationship may have run it's course.
It sounds like there may be a lot more things that you dislike about this girl than you like about her - she isn't going to change these behaviors my friend - this is how she is and since you don't see a future with her, do the right thing for both of you and end it nicely.
you sound intelligent and know what you don't like in a woman now, so keep that in mind when you start dating. Just know that she will badmouth you like she does everyone else when you end it.....she sounds very immature and insecure. you can do better.

Good luck!