Kids Belts Is It A Good Sign When You See Kids Of 10 And 11 Years Old Wearing Black Belts?

Is it a good sign when you see kids of 10 and 11 years old wearing black belts? - kids belts

I was in a Martial Arts Club recently WTF Taekwondo school. In interested in martial arts as in the check-out different styles.
But one thing that has caught my attention in this club there were many children as Black Belts and hey dont get me wrong them.But That is awesome I thought, perhaps a little unlikely?
I thought that took years of training to become a black belt?