I'm really not concerned about the youth team this early in the season. Few of the players know one another, in many cases they've been with us such a short time that they'll have barely trained with their team-mates...
Yes, 5-0's a bit of a kicking, but even if you could find the best 11 youth players in the world and put them in a team, there's no guarantee that they'll manage to string passes together between themselves without getting to know one another's game.
If we get to the last month of the season and we're seeing results like that, then by all means be worried. Not yet though.