There is a lot wrong with this statement.
Ask started to be good when he was 23 years old, which is young. Quick was around 23-24, which is also young. Lundqvist was 21 when he was good, just never made the jump to the NHL. Even then when he came here he was 23 and was good. Rinne was around 25, so yeah that one is correct.
Markstrom has shown he can? Not so sure of that. The AHL is a far cry from the NHL level of talent. Travis Morin, T.J. Brennan, Chris Terry and Corey Locke have shown us that. I think people evaluate him on short little stints here and there. His pre-season has been good, but when NHL calibre rosters are shooting on him he has shown to buckle.