To provide an accurate answer, I would need to know who "he" refers to. If you can specify the person in question, I can give you more information about their performance history.
1998
Since 2007
2006-Present (:
Since 2007
Since April 1995.
Since she was 14 yrs old. She's been performing professionally since she was 15 yrs old.
Since 2010, when they were on the X Factor.
From what I know avril lavigne has been performing since 2003
Maybe a decade now.
He began playing the guitar at the age of 12
according to vedas frm the carnation of ganga(satyug) on earth hindus performing the rituals in this holy river.
she started singing when she was very young, but she started performing at 14