virginity

For some reason, I feel like so many girls are losing/have lost their virginity & some are even pregnant in my school. What I don't understand about myself is why I get jealous about the girls who've lost their virginity. I don't know why I get jealous but I feel like I'm the only one who's a virgin even tho I know I'm not. I feel like I'd get judged if I say I haven't done anything. (BTW this is high school girls)