TOD: I don't remember my first Broadway show. We lived an hour from NYC by train, and my parents first started taking me when I was around 14. I definitely saw A Chorus Line several times, as well as Annie and the revival of The King and I, both of which opened in 1977. I saw Evita after it opened the next year. I remember treating each of these occasions as a near-religious experience, and poring over every word of the programs (including the ads) for weeks afterward.
I also remember attending the out-of-town tryout of Ballroom in Stratford, CT - that would have been 1977 or 1978. I loved it, and was so disappointed the the cast album came out missing some of the songs we had heard there. What a surprise and delight to discover them again, years later, when bk unearthed them on one of his "Lost in Boston" albums.