I was in your same exact situation when I was 19, but unlike you I didnt have the good sense to be careful, wait, and say no. it was the single worst mistake of my life. dont let other people's expectations dictate who or when you have sex. It not like buying a piece of furniture, you cant ever take it back and you have to live with the consequences every day for the rest of your natural life. Take it from me, thats not a life you want to live.