No, there is nothing pertaining to age at the rides, just height requirements (if any).
I would strongly suggest you pick up a copy of the Unofficial Guide to Walt Disney World. It has tons of info on age groups and what rides/attractions were liked best or worst by preschoolers, school age, teens, etc. Really handy book for that sort of thing! Also has something called the "Fright Factor," which describes any potential scary moments for little ones and what to expect.