Club site , Wiki, transfermarket, soccerbase etc all say that White was born in 1997 so 21 in October Not really important as still young enough to not be named in the 25 man squad.
IMHO White would be the natural back up to Balogun and Duffy while Dunk is out and Collins would be on the bench. The problem is the club, somewhat understandably, are very shy with their injury information. and expected time out.
If they consider that Barclay isnt ready the most obvious answer is send him out on loan and create the vacancy to bring in Collins an experienced CB who will most likely never play, but is emergency cover if needed, as we did previously with Forren. The question is who would fill the role...