I think that my first theatre visit was probably to one of the Disney movies when I was a little toddler; probably something like The Little Mermaid or something, although I suppose it could equally have been a Don Bluth animation. Far too long ago to remember now.
I've never really been a big theatre-goer; the theatres aren't too bad back home, but the crowd are a bunch of cretins these days, mainly because the vast majority are in the 10-22 bracket. I think the only time I had a positive crowd was when I saw Independence Day - the bit where the dog jumps through the door to safety drew a huge cheer which was rather amusing. Nah, I've decided that unless the movie is worth it, or is an IMAX, I'm probably not going to bother.