Let's not get too excited just yet - U21 is not the same as the EPL. But playing well among his peers at age level will do his confidence a world of good, and hopefully he can bring that into the Liverpool first XI with him. He's a talented player with youth on his side, and has a lot of EPL experience already, so there is absolutely no reason for so many people to think buying him was a mistake.
But still - he has a lot to learn, and is only just in the door, so let's give him the time he needs rather than showering him with expectation.