Emotional Abuse by Teacher

Try approaching the best students and ask to arrange coaching sessions with them.

I'm pretty sure you could find excellent lessons free online - something that targets your specific needs with precision and subtlety.

I would suggest that after you've graduated, you might make an appointment to see her and discuss the issue.
Prepare yourself in advance, so you go in there feeling calm and factual, not angry or like a victim.
Bare in mind that she thinks you the most talented student she's ever had. That's a huge compliment.
Then ask her what she means by saying you've been her worst student.
Ask her what the specific traits of an excellent student are.

Give her constructive feedback on what worked well and what didn't about her teaching style.
If her instructions don't work for you, why? Did you not understand them? Were they too generalised? Was she using metaphors rather than musical terminology?
Do you have a problem with memory? Might you have done better by taking written notes or recording the lessons?

You could ask her why she thinks your brain was not meant for math or science.
She's made a huge assumption, and I can't see how a music teacher could possibly know that - unless she had some backdoor access to your past educational records.
In general, most people who are musical can also do well in maths and science.
It could be that her comment was manipulative - trying to hold on the most talented student she's ever had. If you succeeded in a musical career, part of the glory would reflect back on her.

Explain the concept of micro-racism to her. She may be completely unaware that her comment on the black covid mask around your arm was racist.
Many whites don't understand that if a person hears many casual micro racisms everyday it can have a cumulative effect (unless you've learned to let it run off like water off oil).

The important thing for you is to consider what you want in life.
The path of a pediatrician takes at least nine years of study and training. The hours for a new doctor in a hospital are long and gruelling. They shouldn't be, because all that sleep deprivation for doctors is disastrous for their patients.
But it's well paid, satisfying to help kids recover, and later on allows you many more choices in hobbies, lifestyle or family. You could always keep you hand in with music as a way to destress.

On the other hand, if you're extremely talented and willing to develop study skills and put in the long hours of practice (average 10 hrs per day for 10 years to reach international standard), you could become a brilliant professional musician. Unless you became a top artists, you'd never earn much, and you'd probably have many broken love affairs (due to the stress of travelling to perform). But you'd have a wonderful life being steeped in music, creativity and the joys of playing with other musicians.

Regardless of what you choose here, stick with what you feel is right for you. Trust yourself.
Even if one path turns out to be a mistake, one can always choose another.
Either way, you get richly fulfilling personal experience.

I think you should continue to work toward your own goals and not take her advice.

If she asks about the mask again, ask HER, "Don't you think ALL lives matter?"

She's racist