what about the fact that you have
5th graders who are this old?

Therein lies the problem!
I was telling someone the other day that about how freaky my 7th graders are--they party like rock stars. And they were like "7th grade!!" But I had to tell them that I have 14, 15, 16 year old 7th graders. They're the same age as juniors in high school and how many juniors did you know having sex? EXACTLY!!