It is fun, but the characters at the 2 meals are very different - British Disney for breakfast (generally characters from Pooh, Alice, and/or Mary Poppins) and Cinderalla (Cindy, her Prince, Stepmom & both Stepsis) for dinner. The character interaction at dinner, apart from Cindy & Prince, is geared more towards older kids & adults; only you can tell if that's really a good fit for your 3.5 yr old. Stepmom is appropriately evil and the Stepsis are hysterical but 3.5 may not 'get it'.
That said, you can also get Pooh characters at CP for all 3 meals. Breakfast at CP has an especially good reputation, and you get the bonus of already being in the park.
For that age, you might strongly consider lunch or dinner at CRT (2 TS) or Akershus (1 TS) instead if the draw is pure princesses. For the classical Disney characters, look into dinner at CM's - also at a monorail resort so no real difference in travel time from 1900PF, and you get the Fab 5.