My 2 cents -- address behavior not age.
I was about 5 or 6 when my mother took some knitting classes. She didn't have a babysitter so I went along. I was a quiet and shy child so it wasn't a problem for anyone. I only have a faint memory of going along. Mom probably had me take a book or some paper and crayons. But also, I was used to entertaining myself while my older siblings were at school and we didn't have close neighbors.
I can see where some workshops might be limited to over age 10 and actually quilting or even over 18 (adult only).