Hi Making Changes, I think the fact that you are able to realize your own weakness or insecurity is a big step!
Since you say you can not afford to move out I am thinking that you may just have to have the "big talk" with mom. Explain to her that you would not hurt her for anything but that you need to make your own decisions, come up with your own ideas and do what you feel is right in whatever situation. Tell her you appreciate her input, but you need to do what you feel is the best for you, whether it be right or wrong. Mistake or no mistake or you will never learn. If she does not want you to be private about everything you do then she will have to accept your choices and let you grow. You need to find out for yourself that you can make wise decisions. And know that it is ok to fall down as long as you get back up.