@farmerman,
You young whippersnappers have a long way to go to catch up with me at 81.
BBB
A whippersnapper is 'an unimportant but offensively presumptuous person, especially a young one'.
A few nineteenth-century examples: "Dost thou think it's nat'ral noo, that having such a proper mun as thou to keep company wi', I'd ever tak' opp wi' such a leetle scanty whipper-snapper as yon?" (Dickens, Nicholas Nickelby); "They think I am very stiff and cool, most of them, and so I am to whippersnappers" (Louisa May Alcott, Little Women); "...had unnaturally been jealous that a young whipper-snapper of a pupil...should become a Parliament man" (Trollope, Phineas Finn).
The word whippersnapper--which, as these citations indicate, is often hyphenated--is first recorded in this sense in the late 1690s; there's an example earlier in the seventeenth century, in a book about criminals, that seems to mean 'a rogue; petty criminal'.
Whippersnapper is probably a blend of the earlier whipster and snipper-snapper, themselves first recorded in the late sixteenth century. Snipper-snapper is now obsolete or dialectal; it is based on snip-snap, a gradational compound having various parts of speech all generally referring to "snappiness," as of conversation.