First of all, make sure you're in a state where having sex at 17 is legal. Don't want your boyfriend to go jail for statutory rape.
I, personally, recommend waiting until 18 to be safe. You can just find a boyfriend and date him until you both come of age. To be honest though, I think you'll be outted as bisexual for the mere fact that you're with a boy. So that's important to think on if you wish to remain closeted for a longer period of time.
To find a boyfriend in the first place, join an gay club and get to know the members until you find one you're attracted to.
In the event that you do have sex while still 17, please use condoms.