Yes, he's going to make mistakes, and yes he is young....but every keeper will make a certain amount of errors per year. He won't do an Almunia. They guy has enough bloocks to be able to shake things like that off, and it won't destroy his confidence like it does Gomez, Green and Almunia.
We need strong personality, and he will only get better and better this lad.
And I think you'd find a keeper with a stronger defensive unit in front of him would do miles better, whoever you had between the sticks.