The best sort of classes don't allow new people to join when they want and also they tend to keep most of their original members.
The one I went to does puppy, adult beginners, intermediate and advanced and also 1-2-1. If you both enjoy the classses and go up through the ranks as it were the dog school I go to also has a display team if anyone aspires to that level.
It might be worth looking round for other classes or may be try agility or flyball.
I've done puppy classes with both of mine and 1-2-1 with Ruby (now 20 months) and when I have time I'm putting her into the intermediate classes with the same club. Wilf (6 months old), bless him, if all goes well with his health I'll be training to be a pets as therapy dog as he'd be more suited to that.