I have the same concerns about my DS3. We have alot of good pre-ks around here but I can't afford them.
We have found "Family Fundamentals" it is a free play group funded by the United Way. It is a school like group that has organized education activities. You could check to see if there is anything like that in your area.
My DS usually calls kids his age babies and likes to show off what he knows. I think I would have problems at a reg Pre-k.
You could always do the try it and see approach and keep looking for the right play date friend!
