VERY good article of out Parents.com! Click the link above to read it!
I would just like to point out that wheelchairs for children, especially children that young, are ridiculously expensive, and therefore many parents choose to have their children use strollers until they are absolutely too big for a stroller or the child is ready for more independence. I know I was in a regular baby stroller older than most children use strollers, and after that I had a specialized stroller pushchair made specifically for children with disabilities. It was inexpensive and easy for my parents to fold up and put in the trunk of the car. I used this stroller until I was about twelve. I know people with disabilities, particularly CP, that have used stroller-type pushchairs well into their teenage years. So when you see someone in a stroller, don’t judge!