Is she too old for me?

I don't think she is too old. As long as you guys have a mutual relationship where you both like or love eachother equally, I think it should be fine. Now it may seem weird because you are only 17, but really u guys are only 8 years apart. When ur 20 she will be 28.. I mean if age difference is really a problem for you then I guess, but I don't think it is that strange as long as you BOTH feel the same.