bri-marie gives excellent advice. But I just thought I'd add that I looked up Pennsylvania laws for you (your profile says you are in this state). Sixteen is age of consent there, so sex with your boyfriend would be legal. I'm saying this because in some states, it would be considered statutory rape. I'm telling you this to reassure you that you would not be breaking any laws,
link.
As the attorney points out in the site linked above, just because it's LEGAL does not mean it's the right choice for you. I'm just cautioning you and asking you to think about your choice, before you do it. I'm not saying
don't do it, because it
is your life and your choice. I'm just asking you to think about if you're ready or not and if you're comfortable with it and doing it for the right reasons.
As bri-marie points out, the first experience is different for everyone. Nine out of ten times, it hurts for girls, at least a
little bit. So if it hurts, I just wanted to let you know that that is
normal, and it's also normal if you bleed. It's OK to be nervous and a little scared. It's a scary thing. Which is why it is important to be
ready for it. You don't want to go too far too fast, before you can handle the physical and emotional consequences.
As always, be safe. Use a condom, and probably see a gynecologist beforehand. These doctors are excellent resources for all your sexual health questions, and what you talk about is confidential. You can also ask for a prescription for birth control from your doctor. If, for whatever reason, you can't or won't go to a gynecologist, than try and be as informed as you can. Talk to your school counselor or health teacher. These talks remain confidential until the point where your life is threatened. But in these matters, they are contractually bound to respect your privacy.
But what I can't stress enough is
be safe. Be sure you'd be willing to deal with the worst case scenario (pregnancy or life-long STD) if your protection for whatever reason fails. Be sure you both want the same thing out of this experience, and that your boyfriend is not using you just for sex. Or, if he IS just using you for sex, is that OK with you.