When did the word teenager come into use ?

I couldn't find the William Manchester reference to the origins - he mentioned it in "The Glory and the Dream", but here is a similar explanation:

Teenagers

The words 'teen age' first appeared in print in the Victoria, British Columbia, 'Daily Colonist' in 1921. It contained an item which invited "all teen age girls of the city" to attend a mass meeting. 'Teenager' - as one word - seems not to have appeared until it did so in an article in 'Popular Science Monthly' magazine in 1941. Both possibly existed in speech prior to these dates.

(aside) "teen" as applied to an age group is first noticed in print in 1673: -online OED

"1673 WYCHERLEY Gentl. Dancing Master IV. i, Your poor young things, when they are once in the teens, think they shall never be married. 1693 Humours Town 98" -online OED