First off, enjoy that cute little cute little body while you have it. Wear a two-piece at the beach this summer if you want! All those guys that have taken turns jerking you around for the past few years? They won't stop until you're in you're twenties, so take it all with a grain of salt and keep moving forward.
Most of your friends now won't hang around after high school, so enjoy their company while you have it. Those girls you've known since kindergarten though? They'll always be there if you need them.
You're not going to get married until you're 29, so just stop fretting over it and enjoy your friends and family. Indulge your creative side because eventually that's what you're going to turn to for a career that makes you happy.
If there is one piece of advice I could give you, if it feels like it's all happening too fast, it probably is. Don't make big decisions without a lot of prayer and wise counsel. You'll learn that eventually.
Also, make amends where you can and savor all of your relationships with family and friends. Some will end too soon.
All my love,