hi Kanga, I just pulled ds out of the waldorf parent toddler program because I felt he got stressed. And its such a lovely enviroment and toys etc etc, I would suggest just be open to whatever your son feels ok with!
This experience made me feel like theres nothing like home for ds you know, home the way it is, the way he knows it, its really home sweet home for him.
I was all excited to go myself but he didnt really seem to need it, it was more for myself I guess.
Maybe later he will like it a lot, well see.
Your babe might just love the montessori program, if you want to give him some familiarity with it you can sing some songs from the program or play in the way they do there, same kind of toys and materials, still the change is going to be huge because is a different place with more people, noises, smells, etc etc. But if he knows some songs or games that might happen, he will feel more like "hey I know this"!