He's not ready to be in the first team squad, but he is probably ready for a debut.
In the u23's I think you can see he's got a bit to learn and he doesn't quite run rampage like he does in the u18 formats. He's still very good and one of the best on the pitch, but it's not like this when you feel it's unfair. When he is, and does it for half a season consistently then I think you can say he's no longer growing in the u23s and either has to step up or have a loan.
You've got to remember he's 16. He's physically developed for a 16 year old playing against 18,19,20, 21 year olds, but he's still a child.