The first show that I ever saw was a tour of Peter Pan with Cathy Rigby when I was 4 or 5 years old. I went with my grandparents (if I remember correctly, the tickets were a gift of some sort - whether it was a birthday, Christmas, etc, I have no idea) and I was completely enthralled with the whole thing. I loved the idea of people getting up on a stage and singing and dancing and telling a story in such a way. And of course, being so young, the flying around the stage in this particular show seemed like real magic to me.
In second grade, my mom and stepdad took me to see a family friend's daughter in a community theatre production of Annie - she was in the ensemble of orphans. Until this point, I never realized that regular people could be a part of theatre as well, and it didn't have to be a big, expensive production to be good (although, this production of Annie was not. I didn't care at the time). As soon as the show was over, I got my mom to get audition information for this theatre's upcoming shows, and I got cast as the Prince's Royal Grand Duke in an all-children's production of Cinderella that they put on. This sparked my love of performing, and I've been doing it ever since.
Over time, performing in shows led me to become aware of other shows that were playing on Broadway (mostly from the savvy theatre folk talking about them) and I started purchasing cast albums and watching movie adaptions of musicals, and from there, my love of this art grew and grew and put me where I am today, and it even still continues to grow.