This context comes from the Steven King's novel "The Shining"
"-You're asking me all this because you're worried, aren't you? Why are you worried about us?
Halloran put his large dark hands on the small boy's shoulders.
-Stop (he said) It's probably nothing. But if it is something..well, you've got a large thing in your head, Danny. You'll have to do a lot of growing yet before you catch up to it, I guess. You got to be brave about it.
- At a future time; eventually: may yet change his mind.(American Heritage® Dictionary of the English Language)
- Besides; in addition: returned for yet another helping.(American Heritage® Dictionary of the English Language)
Does the sentence mean that Danny has "a lot of growing to do in the future" or "a lot of additional growing to what he already did"?