How can we find out what rides a 4 year old can and cannot go on?

I had a similar question when we went. My daughter is four and there were only a few rides she couldn't ride, due to her being 40 inches tall. The rides with restrictions are all height based. I believe the Disney park app displays the height restrictions for each ride.

It is all height based.

There are lots of Customer Service stands in both parks . If not ask when u walk thru the turn styles. Always ask ........ 😁😁

Go on line, there is a hight requirement for most rides, however some your 4year old can ride with you. I also suggest making reservations for the character breakfast. Most of the popular characters walk around while you eat breakfast. Big photo opportunity.