I took a few weeks of classes at a local school that has a good school-age program. Overall, it was not a good experience. The classes were run more as an "open gym." People just showed up and trained whatever they wanted. Nominally, one of the coaches was there to offer advice and help you, but in practice I never got a lot of actual coaching beyond generalities that I figured out for myself.
Almost all of the people at the adult classes trained tumbling, including a group from a local wushu school. I was mainly interested in handbalancing and rings, so I didn't have anyone to partner with. After a few sessions, my training was mostly handstand practice -- which I can do at my regular gym without paying $10 a session -- and basic conditioning on the rings and bars, which has some benefits, but not enough to justify the cost. If I was really serious about ring training, I could just buy a set and start working on muscle-ups and cross pullouts in the comfort of my own home.
If you choose to do it, I'd pick just one or two skills to train at a time. Don't try to train every apparatus. I'm sure I would have built some proficiency if I had stayed with it, but only one or two sessions per week makes it hard to learn a bunch of skills simultaneously.
Also, the first few sessions made my forearms and biceps very sore. Take it easy and don't push to your limit until you've adapted to the training.
Even though this was a pretty negative post, I don't want to dissuade you from doing it. I haven't practiced handbalancing much since I quit -- if anything, blocking out a dedicated gymnastics session forced me to train those skills. I have other commitments that keep from going back now, but I'm moderately interested in returning and focusing only on tumbling.
Just take into account the real amount of coaching you'll be getting, the general interests of the other students, and the skills you actually want to learn.
"The enlightened never cease forging themselves."
-- Morihei Ueshiba