Adults learn sign language in order to work as interpreters, so why not?
It's funny how skewed our perspective can get gearing so much toward early intervention that a kindergarten age child seems "too old to learn."
My 3 year old is over-the-hill, it seems.
Yeah, I'm in the same boat. My two-year-old seems like an ancient dinosaur to me now!
It's never too late. Two years ago, I learned about 500 signs after taking some classes that the local community offered. In kindergarten, we were taught the alphabet, and I've known it since I was around six. It's definitely not too late. Do try and tell us about their progress!