I'm noticing a lot of magazines will review acts like the Artic Monkeys and Lily Allen and say their biggest flaw is their youth. I kind of see that as a cop out. In the 60s when someone wrote a good album people didn't care about age. They just excepted that a teenage Stevie Wonder, Janis Ian, Joan Baez, Steve Windwood and Michael Jackson were good. Now it's like as soon as someone's age is obtained the band automatically gets downgraded and instead of talking about how great their recent album is critics will say they have potential. Sonic Youth were well into their 20s when they first started releasing records. Their early work wasn't as praised as their music from the late 80s to now. So how can youth possibly be used as an excuse to dislike a band?
I'm not too sure about Arctic Monkeys and Lily Allen but usually when a critic writes that they mean that the artist has made some naive blunders that most likely result from inexperience. Some artists (like Joss Stone) sound mature right from the debut. Some (like Neil Young, God bless him, his last album was pretty ridiculous) sound like they're still learning how to make a record.