I started taking my youngest daughter before she turned 3. She doesn_t remember much of it, but Mrs. Obviousman and I do. We have wonderful memories of our youngest on the rides at Disneyland, and the pictures to prove it. She doesn_t remember back that far (most long term memory doesn_t start until 4 or 5), but she enjoy the memories and you will too.
BTW, this is an excellent time to go. The lines are the shortest of the year.
However, while they are there, they will get a sense of the Disney Magic that they may not remember specifically, but it will stick with then nonetheless.
Hope I helped!
But NOT the california adventures part, which is the best part of all.
=)
I think it would be silly to take kids under age 3 1/2.
Have fun!
wait a year maybe so they will remember it :-) x