Puberty is on the horizon (I think)

The setting: A weekday morning, we are doing our morning routine, getting the kids ready for school. I am in the girls bedroom helping them pick out their outfits for the day. Jeffrey has just gotten out of the shower. He then runs, completely naked, into the girls room to find me and excitedly yells,

"MOM, I HAVE MY FIRST ARMPIT HAIR"!!!

I must be honest. I looked very closely. I can't seem to find it. He sure was pulling on something though. You decide.