Well i guess im a fairly experienced senior (3 girls). I didnt lose my virginity until junior year, and it was to a girlfirend (she was smokin'). Sex is fun, but its not like "WOW that was the coolest thing i have ever done". It's incredibly fun, don't get me wrong, but its not too much different from getting head. I'm just saying don't focus on tryign to get laid, it's not that big of a deal. If you want to save it till marriage, thats your own views. In my opinion, almost everyone has been sexually active before marriage so when looking for a virgin wife, it will be even trickier for her to fit your criteria.
You are in highschool man, live it up, you're only here once. You can get girl pregnant, but ive had unprotected sex more than i have with a condom, and im no daddy. It's risky and dumb, but whats life without a lil risk
. Diseases aren't too common in highschool, but don't risk it. Make sure you dont hook up with a chick who gives it up easy because if she gave it to you easy, who else has been there.
If you wear a condom, you should be good. The only thing about condoms is make sure they are newer, because i used an old one once and it burst.
If these chicks are worth your ****, my advice would be to pick one, get serious, and get busy man. You'll only get to be a senior once. Good luck.