I started my class when I wanted, but I did it by myself. I don't know if they are going to have a group do it together so you get more interactions? They should send an email back to let you know what is planned. I know Sarah is working on an updated version of the training manual. Perhaps that is due to be finished in Aug and she wants to hold new people until it is available?
Even if you can't officially start, you can work with your buns to make them more comfortable. You can get them used to riding around in the basket (I use treats to bribe them to jump in and then would cary them around the house). They stay in the basket better during a visit due to unfamiliar territory, but it's good to get them used to it so it is associated to good things and a safe place.
I also take my rabbits to pet stores and have them ride around in the cart. At first it was a little stressful for them with all the new sounds and smells. Then they connected the trips with getting to pick out treats. I will put down two kinds of hay for them to sniff, Becky is great at telling me what she wants. Then when they get home they get the treat hay. Gradually over time they became energized and curious when we went to the store. Now I take them to the park and all over the place in their stroller.
Getting them comfortable with being out and about I think is one of the most important steps because then it will be easier to add the people component. The goal is to have this be a mutually beneficial interaction. Becky and Gary look forward to their trips out and love interacting with the people. The people love the visits, everyone wins.