Honey, I *am* a professional flutist - and a teacher of over 35 years experience, as well as a competition judge. As the other responders have said, you absolutely must have been studying with TOP teacher of your instrument for many years, and have won many honors and positions in highly advanced groups (like All-State in your state, as a minimum!) to even think of applying to a good music schools. Are there some colleges that will take you anyway? Sure - but they will never ever prepare you to be competitive when auditioning fr a career. There are things that are fundamental that you might have learned on your own - but it is possible that you learned them inefficiently, or just plain incorrectly. And there are many things that you have never even *heard* of, that you need to learn as well. When I take my students to that next level, it's like Willie Wonka opening the doors to another whole room of delight - overwhelming, and then *wonderful*!
As far a colleges, again - if you go to some lesser-known,m or even mediocre place, you stand ZERO chance of a seat in a full-0time professional orchestra. I have a former *vocal* student who now hold a BM and a MM from Juilliard as a horn major, is in a professional training program at Curtis - and still is unable to land her first full-time job. Another friend - she and her husband are both retired from the horn section of the Met Opera orchestra - have a horn-playing daughter who played in the Far East for 11 years - and has given up of getting a horn job in the US or Europe - and she also has Juilliard-and-beyond training. I am an All-State judge in NY. Every year, out of the thousands of just *flutists* we hear auditioning for AS, we get maybe 400 or so perfect scores. Out of those - we take just over 20 into groups. Yes, there is something that needs to be fixed in the system - but even so, the level of playing is *astounding*. And you would be competing with that - for college, and for professional jobs.
There is a place in life for everyone - and you might someday find a group that you enjoy playing in, for fun - but please do not set you sights on this unrealistic goal. I play professionally, but never have played in any major orchestra - I chose my goal decades ago, to chamber music and teaching. I enjoy that, and can make a genuine contribution - and a very good living. I know where I am in the Food Chain of Flutists - I go to conventions, I listen to live concerts and recordings, and learn a great deal - and know just how I can help the future generation of flutists. Keep playing the flute, and I hope that your college education leads you to a career wherein you have all the security and income you need, to THEN study at the level you cannot right now. All the best.