How old are the main characters from glee?

rachel (lea michele) is 23 years old
finn (Cory Monteith) is 27 years old
noah/puck (mark salling) is 27 years old
quinn (dianna agron) is 23 years old
will shuester (Matthew morrison) is 31 years old
kurt (chris colfer) is 19 years old
artie (kevin McHale) is 21 years old
mercadies (amber riley) is ?? i think shes 21..
tina (jenna ushkowitz) is 23 years old