Wrestling With My Own Intentions

I, 16M have been dating my girlfriend 17F, for 3 months now. I am extremely attracted to her, in every way. From even before we started dating, she made it clear that she was not and would not be ready to be intimate for a long time. This is due to the risk of pregnancy. I respect her boundaries, but do know I would want to be intimate at some point long before I would be ready to have children. The problem I am wrestling with is if I am with her just for sex. I know I care about her, and genuinely do feel excited for her, and sad for her during appropriate times. We just have very different interests and certain things she does I wish she didn't. I do want to be better for her, and I miss her when she isn't around. I guess the main problem I'm having is one part of me thinks it's not possible that I could have overcome my shallowness. I know previously I was shallow and honestly I would've changed myself for someone so I could have sex. My question is, is this type of doubt normal? Should I be open about this to her? What can I do to overcome this feeling?