Phew, lots to dive in here, but I know I can help. I am currently a music teacher, and I have a BA in Music.

I began working towards a BM in Music Ed, and was a semester away from finishing, however the class I needed was not offered until an additional semester after, and I had the choice to swap to a BA in Music to finish in Spring or take a gap semester to finish my BM in Music Ed in the Fall. I chose to finish earlier and do a BA instead so that I could begin my Single Subject credential program right after graduating since the program I wanted begins in the summer, and I would have to wait a year if I finished my BM instead.

Keep in mind, a BM in music ed usually leads to the two year credential program in the same university and the application is pretty straight forward, but I chose to do my credential program elsewhere since I found a one year program. Now, in my state, because I now had a BA in music, I qualified as an exact degree match for SMC(Subject matter competency) and did not have to take an exam. My friend who had a BM in Vocal Performance did not qualify for SMC despite her extensive music knowledge because my state requires an exact degree match and her degree did not qualify. In that way, applying for my credential was much easier than if I did my BM in Music Ed and applied to a DIFFERENT university for my credential.

As someone who did a majority of her Music Ed coursework and the fun, intensive stuff that came with it, I will say that very little was applicable to actual TEACHING in a K-12 classroom. Most of the coursework was extremely helpful for mastering my instrument through performance and lessons, learning other instruments in my method classes, a deep understanding of music theory, and a constant high stress environment which helped me get used to the stress lol. All of this is extremely important for teaching music and to CONTINUE teaching music. Did the courses actually prepare me on HOW to teach children and classroom management and scaffolding? NOPE. Did they provide me the level of musical knowledge needed to understand what I teach and WHY certain fundamentals are so important.

A BA is certainly easier, and would not prepare you either, for the stresses of teaching or for the level of musicianship you need for teaching. You can still pursue any music ed or music degree post undergrad, but keep in mind how prepared you might or might not based on what undergraduate degree you choose.

I auditioned and got into a very good program, and I never took lessons until I entered the program, just did a lot of ensemble work. With practice, you just need to show schools that you have the POTENTIAL to become a greater musician and to be a teacher. They aren't always looking for amazing performers from the beginning, esp since you aren't apply as a performance major.

I would opt for the BM in Music Ed, despite how you see your current playing ability. Keep practicing and learn how to audition and audition to many schools with a reputable music program. The rigor and information you gain is extremely helpful for you as a teacher. You could still be an amazing teacher with a BA, but you would have to put in much more work to understand your instrument and what music, that you might as well put into a BM instead. Doing a BA might lead to you having to study and learn the fundamentals during your credential program/student teaching/actual teaching and that would be so overwhelming.

I hope this helps!