My 7 year old has a twin bed. He is very big for his age, at 4'10" and 100 pounds. I feel like he may be big enough to transfer to a queen bed. My husband and I both had twin beds until we moved out on our own, so that is what's holding me back from buying him a new bedroom suite. What do you all think? When did you transfer to a queen bed? Is he too young? What is the right age or size to change?