damn! what happen to kids nowaday? All they think about is sex sex sex. I think the media rotten their mind.
Sex does not bring you connection to a person when you don't know what the heck you're doing with the relationship. In your case, you're 15 and you're being pushed by your friends to have sex with your gf. It's a shame. You and your gf are so young and here you are wanting to get laid. Where the innocence of a teenager goes?
If you really think this gf is special, stop thinking about screwing her. She's 16, she'll hate you later for taking her virginity!