I am finishing up my second year at The Theatre School at DePaul. In the last 2 years I have learned more about this job and the industry than I even knew existed while I was still in High School, and look forward to learning much more.
It's great because we learn how to speak the languages of all other tech/design areas by taking classes, while diving straight into ASMing and SMing both storefront-sized and Broadway-sized shows. We get a well rounded education in theatre, and it's very focused and intense.
For any high schooler who wants to be a stage manager, I highly recommend this program. It has it's flaws, of course, but the advantages (being in the city, professors who are working in their fields and can hook us up with jobs, lots of hands on experience!) certainly make it a great place.
Feel free to send me a message through here if you want to talk any more. The Theatre School Admissions office also has an AIM screen name that you can IM if you have questions (TheTheatreSchool) and my name's Anna, so you can ask if I'm working and we can chat about it.
Happy Exploring!