To examine the different aspects of studying composition as major, I'd like to mention about the least adequate environment first.
Whether if you have aptitude for music or have fundamental or advanced knowledge of music, you need to make your living. That may sound like I'm a capitalist oppresor, yet my statement is considered true. You need to provide yourself time, and optimum money in order to be mentally and physically 'ready' to compose in this time you provided.
Now that you have these two provided, let's consider about what you may do in your time.
There are several possibilities which are:
-Choosing composition as major
-Studying something else at uni, and studying composition on your own or with a tutor.
-Studying composition on your own without going to any school.
Third option looks unlikely (yet possible), however first two are quite possible.
Now to talk about uni, this may help you to see what you can get 'from' school. Think about school as a place that gives you atmosphere of what you are studying, and inspiration. Atmosphere will make you feel connected and you 'belong' to a part of academia. You'll eventually become more adapted to the jargon, thus you'll be motivated by any means. And inspiration will provide you a pill of experience (by teachers)- not making you learn faster but giving you eagerness to delve into more. Having these two essentials not enough until you have the spark that starts reaction, which is a basic knowledge.
Does it mean you can't find atmosphere and inspiration unless you go to school? No, that's wrong. Sure you can find these two, no need to mention knowledge. But! You'll never find educational experience which will make you rocket jump from where you are (schools guarantee they contain tutors, not all tutors guarantee they contain educational experience). You are going to have to find anything on your 'own'. This is really a gamble. I took this path and found rare tools (in exchange of ruined time) which vastly helps me now, in terms of self-studying, however, if you are willing to study composition, it is absolutely wise to combine your eagerness with an experienced tutor's guidance.
This, again, doesn't mean you can't make on your own. But again, seeing where you are, where you go and how to get there, revising and correcting your mistakes quickly, embodying your targets, helps you more than you imagine.
I figured 3 conditions (rather milestones) for myself about how to be a composer. Maybe it'll help you too.
A composer needs to:
- be diligent to build a sound foundation about any subject in music, and passionate to keep up building.
- see the fine line where rationality meets and departs emotions, and grasp their individual meaning.
- be adventurous and valiant to show your works.
Everyone will eventually find theirselves studying on their own, but it's about how to get there.
I hope I helped you a bit.