We do frequently. When the weather is crummy it’s going to be busy and you’re going to be chasing them around just as much as they are running around. 21 months there’s probably a separate smaller kids area that won’t be as hectic but when they get older lookout.
My experience has been that all the parents are on the same page and just trying not to have all the kids get in each others way and get hurt. Your kid will enjoy it.