First musical? professional, amateur?
Between 1958 and 1971, I saw the following:
Jr High School: Knickerbocker Holiday, Where's Charley?
High School: South Pacific, The King & I
College: Brigadoon, Kismet, Threepenny Opera, Babes In Arms, A Funny Thing Happened On the Way To The Forum
National tours:
The Sound of Music
Camelot
Hello, Dolly!
Cabaret
Hello, Dolly!
No No Nanette
Carousel
Camelot
Broadway:
Hello, Dolly!
Man of La Mancha
Oklahoma!
Promises, Promises
1776
Regional Theatre:
The Fantasticks - also, college and community theatre productions
The Last Sweet Days of Isaac
Threepenny Opera
Film:
The King & I (1956)