I agree with MadB - definitely don't give up on it yet. My 4 and 3 year olds still have an afternoon sleep of some kind most days - the 4 year old has about 30 minutes nap at kindy and my 3 year old can sleep for up to 2 hours. They both can go a day or two without having a sleep if we've got lots on, but boy do I notice the change in them when they miss out.