This, and what you said to fawkes makes me believe you're trying to convince yourself that you can do it, which isn't exactly a bad thing. Except it seem you don't accept advice against doing it very easily, even though the topic was made for advice, even if it is a 'no'.
What I'm trying to say is, at least consider a little, I mean she might go to college, and if she does it might not work out for you and her. She might not go to college, but because of the age difference, she may find a guy closer to her age. I mean, it isn't such a big deal after about 20 or 25 or so, but at 18 / 19 it makes a difference. Especially because when she's 20 it'd be adult dating a 16 / 17 year old. My advice is to at least consider what kind of person she is, and if you think it'd work out with college or not. Personally, I would wait if I were you. But, hey, it's your life so I guess it isn't exactly my choice.
There were tons of girls in my high school dating dudes that were like 20 an up. I always though it was weird as forget and the dude was most likely a loser. Just trying to get with high school girls. Though one guy graduated and when he was like 20-21 he would still be making friends with high school kids. He would try to date like an freshman. I thought that was really creepy. I've never seen a girl do anything like the creepy dudes.