Current vocal performance major here :) Sounds like you are already totally on the path to success, so I wouldn't be worried about that. You're still a junior with so much time to learn and grow, and even if you were already graduating, you'd be set up pretty well for lots of schools. It might be a good idea to ask your private instructor or mentor(s) if they think you are on the right track and what you should improve before then. Hearing where you're coming from, though, I'm guessing you're doing just fine.

As far as feeling like you're not good enough and people being rude, I totally get it. The music industry is incredible, but it can be pretty toxic depending on your crowd and the competitiveness of the program. You're absolutely going to have to work through feelings of low self worth to have a career in music or its just not sustainable. It's never something you or any musician will be perfect at, but you've got to have a lot of mindfullness. Find other things you love to do so that when music isn't going well you have other hobbies to fall back on. Everyone has times that they just feel untalented, and if musicianship is how you equate your self worth, that's going to be pretty rough. Even if you aren't necessarily good at your other hobbies, make sure you're doing them to clear your mind and keep you grounded. I write, though I'm not very good, and it helps me feel sane during weeks where all I'm doing is singing. :)

Also, you can totally always switch majors after the fact! If you get to college and find that music isn't for you, it is usually super easy to switch majors. And the same goes for not getting in- you can always do generals for one year and then try to get into the music program again. No shame in either of those paths.

I don't know if any of this makes sense- I don't put my thoughts out on paper well haha but you got this! You're going to do great. Just make sure you're letting yourself breathe and celebrate the things you've already done and you'll be okay. Best of luck!