Ok, so I'm 17 and my girlfriend is going to be 17 in a week or 2 and we've started having sex. She is on BC (I think she got the shot but she told me a while ago so I'm not sure to be honest.) and we don't use a condom or anything because she is. We've had sex 2 times (in a 2 month period) and each time I came inside of her even if it did take me forever.
Either way after the post-orgasmic euphoria wears of I start to become very very paranoid that the BC is going to fail. It goes away after about a day but it still scares me. We don't really want to change how we do it but can someone help me not be so paranoid? I guess my mind thinks that the shot will fail (from what I read it can't fail. Is this true?) but if it was the pill she does it perfectly (she has 1 other pill to take every day so she'd do it at the same time as that one, at the same time every day.
Can someone help me? (I do know all BC can fail.. but I'm just worried.. I don't think she is pregnant but I'm scared she will be.)


Your caution is almost admirable. Comfort, especially for the woman, comes with maturity. All hormonal birth control, including the shot, is about of the same effectiveness. If 100 sexually active women use it properly for a year, three will become pregnant. Those odds are about as good as it gets.
You could enhance the safety by also using condoms. Many unmarried women on the pill also require condoms on their partners. In long term, stable relationships, most women use nothing else. At you g/f's age and experience the condom should be included and the chances then approach nil.
ahem: [SIZE="6">ALWAYS USE CONDOMS[/SIZE], you're welcome. Regardless of what she's on - you do NOT need the complications or worry. Please, do not be stupid and go without, "bareback" really is not the safe choice.
Yea I would use some other backup method whether its condoms or spermicide... the worry is not worth it! Especially since you aren't even sure what type of BC she is on and like you said... if it's the pill... is she taking it religiously? etc.
Also, you mention, it took you forever to come. That can happen... especially in this situation b/c in the back of your mind.. those worries of getting her pregnant work to sort of "block" the orgasm. When you have no worries and can relax... orgasms come much easier! for both sides :)
...and one more thing to add to the above. How are you building your arousal to the point of an orgasm? If you are stroking and stroking and stroking in order to get to the brink then you are going about it in the wrong manner. If you are already at the brink of an orgasm yet can still maintain enough control to get into position, then you are doing things correctly. You should be devoting lots of time to making out before ever getting to the foreplay stage and when you have reached the point where you are about to climax, pause, get into position--then begin stroking. You shouldn't have to do much stroking or thrusting.
If she is taking it properly, things should be ok and there is only a small chance. However, if you are becoming paranoid about it then you should use a second method like condoms. If you were comfortable, fine, but being paranoid is not good. And at that age you should get used to the feeling of condoms because you should definitely use them with new sexual partners.