Well it's good to start looking early; the more you understand and know now, the easier it is later on.
There are now close to 30 schools that offer the ATC-CTI program. See: http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/acquisition/aja51/cti/AT-CTI_Schools.cfm
You do NOT have to go to school to become a controller. The FAA accepts applications off of the street. However, THOUSANDS apply to the application that comes out maybe 2-3 times per year. Personally, it's not the best way in. It's not impossible, but it's not the best. The process is long, drawn out and you'll spend an extra month in Oklahoma City, OK for training if they select you.
You're young. I strongly recommend a CTI school. There are almost 30 to choose from and some of the major schools offer a 4-year program. If you're unsure about the major when you get there, those 4-year schools offer other majors and you'll have already completed some of your electives. You can always switch majors almost no matter where you go (I did). I went to a CTI school (Community College of Beaver County www.ccbc.edu
), which is one of the best ATC-CTI schools in the country and the only one that has a REAL air traffic control tower that you get to control real aircraft in. I would have never applied for the job if I didn't attend this school. The FAA just offered me Cleveland Tower, too.
I strongly suggest that you start contacting some of the schools you're interested in and request information and a tour and to meet with the program director. Ask questions and explore your options (there are many).
You do not need to go through the military, either. While the FAA will hire people who have gone that route, it is only one of three ways the FAA hires controllers (military, ATC-CTI, Public).
Also, check out the FAA website. They have lots of information on becoming a controller. They also have the entire Air Traffic Control manual online (FAAO 7110.65S - Air Traffic Control). It's a large PDF file with all of the rules and regulations on controlling along with proper phraseology. Literally, the controller's "Bible." You can find it here: http://www.faa.gov/airports_airtraffic/air_traffic/publications/atpubs/ATC/
Keep in mind that this changes from time to time. The "S" version is current and will change every two years (I believe).
Lastly, keep an eye on my blog (link in signature). It hasn't beenupdated lately as I've been a little busy, but it will contain some valuable information on schools and getting into the profession.
If you have any questions, let me know. Even post a comment in my blog if you'd like.
Hope I've been able to help!