Hi @Confusssssssssed - I don’t know much about vocal studies since my kid is an instrumentalist, but one thing you probably should do ASAP is to take a thorough look at the music offerings at the school you are currently committed to, since that is by far your easiest path to take. I assume they have a B.A. program in music there? If you can get your hands on a course catalog PDF, music B.A. requirements or advising worksheets that music majors would used to select courses, that can give you a better idea of what being a music major is like there, how much performance/vocal training is involved vs. music academics, composition, etc. Find out what vocal ensembles are available and see if you can find concert videos on YouTube. If you have specific questions based on what you see, ask the school’s music department and/or post about it here and it’s likely someone will be able to help.
You also might want to reach out by email to faculty members in the music department before they scatter for the summer, especially any voice professors or instructors, to get a better idea of what the program is like and to ask specific questions. Presumably you would want to approach them as an enthusiastic incoming music major rather than making it clear you are thinking about going someplace else. They might be able to share recordings of ensembles or put you in touch with a few current music majors who are vocalists.
This type of information may end up reassuring you that your musical needs will be met at your school, or it may give you more specific reasons why it might be better to defer. Do pay attention to what musicamusica said, though. There may not be very many music school options out there that would suit you and those may be very tough to get admitted to. You may be better off exploring music more generally in a BA program like the one your LAC has. You might want to check out this thread if you do decide to look at music schools: http://talk.collegeconfidential.com/music-major/1666721-contemporary-vocal-performance-and-music-business-programs.html
Consider connecting with a good voice teacher locally who can advise you, assess your voice, and potentially prepare you for auditions if you decide to defer and apply to music programs next fall, because if you decide to go that route you would need to start working on audition repertoire. As you suspected, for music schools it is (almost) all about the audition, and many schools have very specific requirements that you may not be prepared for. Ask your choir director for voice teacher recommendations.
Good luck!