First of all, you can absolutely turn around and change your mind, no matter what happened. Second, if your hiding the relationship from your parents, they obviously feel strongly that you two are wrong together due to everything that has happened, and you shouldn't ignore that sign. Also, you are only hurting this girl and yourself by staying any longer. Lastly, if you do stop talking to her, you have to literally STOP talking to her. Breaking up with her will be hard on her, but it will be harder if you continue to answer her calls and texts after the final break is made, and probably wven make the break up fail. if your going to leave, don't sit there and let her guilt you and beg you for days until you just end back up where you are now. I was in a co dependant relationship for 2 years where I tried to break up for half of that time, but kept giving him the chance to guilt me back in some way. It will only work if you stop communication. You will have to sit through the ringing phone and delete the messages until eventually they stop coming. (Took a whole month in my case for that ex to stop sending messages and calling, even though i never responded).

You don't need an excuse to do it. The real reason you want to do it is good enough. You're young and its hard to know exactly what you want sometimes. it might come off as you were messing with her feelings or whatever else. Fact of the matter is, you just didnt make the right choices in the matter. Fix it and youll both move on. Next time you will actually have the experience not to make decisions for not so good reasons when others feelings are at stake. (Such as.... trying to spare her feelings by agreeing to what you cant truly commit to with her, as in a loving relationship).