Kids age 14 at school already haveing sex?

Ok so today my friend told me that one girl told her she had sex, keep in mind I'm in 8th grade. She said she even gave him a BLOW JOB. I was just dumbfounded, I was shocked that people were actually having sex at around the age of fourteen and I can't believe they're parents would let them do that. But I guess my overall question is that is it normal for people to start having sex at such a young age?