OK
First thing's first- if your GF starts going all wonky, getting emotional and bizzare and generally acting really wierd, have her try another brand of birth control. BC CAN AND DOES mess with your head AND your libido. If her libido tanks, have her try another brand of BC.
Also, MAKE SURE she's got an open dialogue with her OBGYN. If there's ANYTHING she doesn't like about him/her, get her to switch doctors until she finds someone she likes and trusts completely. They're sticking their head in her privvy bits, there's a certian level of expected intimacy involved with that. Rules of engagement do apply.
Thirdly, it's very good of you to ask all these questions. Go to barnes and noble, check out
The Guide to Getting It ON! by Paul Johannes. It's a very, very, very informative book about sex and sexuality, and it will help you and your girlfriend make the transition into having a wonderful and fufilling sex life while being informed and mature about the whole thing. It's not just Tab A into Slot B, repeat.
Some more things:
If sex is hurting her, the #1 reason I can think of is she's not lubricated enough. How long does foreplay last? Is she totally turned on before you start? You DO know she's supposed to get wet, right? And she IS going to go talk to her doctor about sex hurting, right? A lot more women than you would think have shortened vaginas, tilted cervixes... all kinds of strange schematics. Still, it's a good idea to make sure there's nothing actually wrong.
IF she takes the pill at the same time every day and IF she makes sure NOT to eat/take anything that interferes with the pill (and there's a lot of things- do a google on it) then the pill will work 99.8% of the time (I think that number is correct). Chill out- it's the pill, it's been in devlopment for almost fourty years now (or is it fifty?). Enjoy being young and having sex!
Nonoxinol-9 has actually been found to not be as effective as first thought, and some studies show that it can actually have a detrimental effect on attempts to keep sperm from reaching egg. Google this too- I can't think right off the top of my head where I've read that, but I know it was a reputable sorce. As for the latex thing... if you're spending money on the pill, why are you using condoms as well? Like I said, 99.8% effective IF USED CORRECTLY. (repeat- IF USED CORRECTLY).
Lastly, MAKE SURE YOU ARE REALLY, SERIOUSLY TALKING WITH YOUR GIRLFRIEND about sex and all things sex related. If you want to have a really awesome sex life, you have to BE HONEST and encourage her to do the same. Don't be afraid to try new things, explore new boundaries, and have fun!