To young to commit

Ok, I am sixteen, before I get any further. I have been dating my first girlfriend for almost two years now. We have a great relationship, in that we are best friends, have never really had an argument, and have great sex. Although I had flirted with and kissed girls before her, she is my first real girlfriend. Everything is great, except that the other day she mentioned to me that she wants to get an apartment as soon as we graduate in two years, and seems to be keeping where I want to go to college in mind for where she should go. She acts like we are going to be together forever. I do love her, and yet I feel like she is asking for a level of commitment that I am not prepared for.  She is an almost fragile person and I don’t want to hurt her feelings if I don’t have to. Although the idea of going to college together sounds great now, I don’t know how I’ll feel in the future, and I wish she wouldn’t make plans that she might have trouble unmaking. I haven’t even been with another woman, so I don’t know if what I feel for her is real. Should I tell her how I’m feeling, or wait and see what happens?