I remember when Jack Grealish arrived a few years ago at a very tender age, my comment was pretty much identical to yours to be honest, but I couldn't have been more wrong. Callum McGregor didn't turn out bad either. If four clubs are after this lad then they must see something in him.
We are talking about the sharp end of the season with 20 games to go not 46. Age has nothing to do with it really (as Grealish demonstrated) but I doubt whether we will get another Jack so we really haven't got time to get someone up to speed.