Sweet heart, I know that you feel like you are in love with her, but you must understand the large age gap and the fact that if your friends found out....wouldn't they make fun of you?
Now, her friends would be egging her on..."Oh, your going out with a senior! Lucky girl!"
YOU however, would be the butt of all jokes!
I once dated a guy who was in high school, and I in middle. We were only one year apart, but he got the worst of it...
Even though I was pretty and mature for my age, he still got so much ribbing from his friends.
You could try it, but NO SEX! Understand? To many OTHER problems in that area...
I just think that that many years difference will be awkward and uncomfortable for you both.
Blessings and luck