14 year old children are having sex?!

So I'm scrolling through this question on here that was asking what age did you lose your virginity and majority of the comments said 14. I thought the average age was around 16 or so? The characters in these teen shows keep getting younger too. Its like 8th graders and freshmen in serious relationships and having sex. How does that affect our kids? I have 13 year old twins boy and girl and they will be in high school this year. My 13 year old secretly had a "girlfriend" and the only reason I'm letting him stay with her because I know if hes anything like me, he'll keep "dating" her as they're at the same school. But back to the topic this makes me incredibly nervous. I would prefer them wait at LEAST 3-4 more years, even longer more preferably. I dont know what I'd do if my kids did it now. Not trying to sound psycho or overbearing, just a little panicked. Does this scare anyone else with kids around this age?!