What is it like to have been diagnosed with arthritis at a young age?

It depends: It depends on the type of arthritis, the joints involved and the severity of the involvement. The vast majority can be effectively treated so the child can live a normal life.

Cannot say: Some forms of childhood arthritis resolve without any later effects. Others can continue into adulthood. Some cause deformities and secondary osteoarthritis. It all depends on the type: infectious arthritis, lupus arthritis, juvenile idiopathic arthritis (multiple forms), etc.