I have several learning difficulties: Dyspraxia and dislexia. I know people on fb who are getting diagnosed at 17.
I thought that you get born with it - not acquire it, or perhaps acquire it a very young age iirc.
Just because the diagnosis is late doesn’t mean they haven’t had it since birth. Some people don’t get diagnosed until adulthood, and others who could benefit probably never do (I have one adult friend in his 70s now who comes to mind!). So what is your question? And why did you post it in this forum?