Hank, mandolin is an excellent choice for a first instrument. And I like your decisive strategy. Only thing I'd suggest you do differently is, pick a likely-looking pork chop --bluegrass nickname for mandolin--(in your price range--I'd suggest $200-300, probably not less) ask to borrow it seeing as you're staying on the premises, and ask your teacher's opinion of it before you buy. (Out of earshot of the sales floor.) It's quite possible to get a good playable one inexpensively, but there is also a lot of unplayable, untunable junk in the lower price ranges. I've been playing an $85 mandolin as my main 8-string since 1989, and its done me great service. Not that I don't covet a Gibson...

Mandos have a lot of advantages: highly portable & durable, not too difficult to learn, excellent for fiddle tunes in many different styles--Celtic, bluegrass, old-time--there's rarely too many of them at a session or jam, and nobody makes jokes about them. The small fingerboard flummoxes many people, but it means lots of notes within your reach.

Tuning them is a bit tricky, but not too bad. I have a theory which I intend to try sometime that a 4-string mando (removing one of each pair) would be an ideal kids starter instrument, easier to finger and tune than the standard 8.

Plus, once you learn mandolin fingering, you can try picking up fiddle, or larger members of the mandolin family, to get a different sound without starting from zero. Go For It!

Bill Plunking Away in the North Woods Despite an Uncertain Future.