Pre-teen: self-explanatory really, <13
Tween: those 11s and 12s with the physical and/or emotional and/or financial attributes of a teen, usually f
Teeny-bopper: a teen before they become rebellious, almost always f and associated with really bad music
Teen: again self-explanatory, 13-19 inclusive
Adolescent: a teen who is too cool/mature/rebellious to be called (and treated as) a teen