I am going to be disagreed with most but binding young is bad and worse then as an adult. If you bind tight (it might hurt but be the only emotionally comfortable way), for long periods (i.e. only remove it for showering or sleeping), wear it for more then 3 years during puberty or adolescence or bind more then just your chest (i.e diaphram) then it could be a serious problem.
When ever you have youth who is binding, you stand the chance of malformed bones from the constant pressure, inflamed soft tissue between ribs, upper and lower respiratory infections and damaging the underlying chest muscles. I suffered all of these problems binding since they showed up at puberty. I only stopped after surgery. There is even a group of scientists that have suggested that some breast cancers are caused by bras interfering with lymph drainage. I personally don't know about that but if it is true FTMs who bind would be at a far greater risk.
Nothing would have changed for me as I knew the risks. You can try to slow down the effects by doing lung drainage similar to that used for those with cystic fibrosis. I know youth who have tried or succeeded in killing them selves when the option to bind was removed from them others just went to tape. I think the option of short term binding combined with prompt surgery should eliminate or change those risks.
->-bleeped-<-boy