Honestly, I feel you'd be glad for not having sex too early when you grow a little older. You are an adult and you have all the rights to make your own decisions and at 19, your friends should be able to understand that. I was eighteen when I lost my virginity to a girl on whom I barely was in love. I was just infatuated. I am 26 now and my current girlfriend is just so special for me that I regret having lost my virginity to a girl I never wanted to spend my whole life with. It is best to "know" the right time to lie next to someone. And when you do find the right person, you will know it by default. Don't listen to your friends, I advice.