Waiting.

I'm 17 and I have decided to be abstinent until marriage.... I have no issue or temptation as of now but the problem being is my Christian friends are having sex with guys and they are all younger than I am. I'm struggling due to the fact that I'm almost shamed for waiting for my husband. One says that she has sex for practice... And of course it's enjoyable. I'm just not sure why she thinks it's so amazing to break Gods word... I'm struggling to not go into my friends mindset on sex....