Talk to your SM or DM, that's unacceptable.

Yeah that's not okay. At no point should any leadership be yelling at you, or even scolding in such a way. Telling anyone, male female or enby to "man up" is fucking gross and sexist to boot. Loop in ethics or hr if you don't trust your SM to have your back.

Edited to add: The moment you cut yourself you should be off the floor until you're cleaned up and covered. It's absolutely a health hazard to everyone involved. You did the right thing.

Yeah, if anybody in the store yelled at me regardless of their position, I’m going to HR. Best nip this in the bud before it escalates (and it will escalate)

Hey, five year partner and ssv here,
First of all I’m so sorry to see this is happening. If I were you I would do a few things.
1) You can confront her directly. You might feel more comfortable writing down your concerns on a piece of paper. And also if a shift you trust and recognizes the problem is there. Starbucks can be a shitty place to work but at least they set up the “connect” system for us to talk to people. Anyways you should really tell her that how she coaches partners in entirely inappropriate and belongs nowhere in a modern workplace. Second, you are not a child (I’d assume you’re not, even if you’re still a teen) and you should not be spoken to like one. She NEEDS to show you and your coworkers with respect if she ever expects you to show her any. As a superior in work she must earn respect and by HARASSING AND BULLYING partners she is only creating an unsafe and hostile work environment.
It may seem like a lot to confront someone with this kind of information but if you genuinely enjoy working at that location I think it’s worth a try. People like this thrive on feeling superior and they believe no one will call them out on it. Once you do they back down.
There is the chance they’ll react extremely poorly and get even more upset with you. That’s why having a witness there to be a mediator and a witness to how you reacted vs them is crucial and I don’t recommend doing this if you don’t have someone you trust there.
2) There are other things you can do, like writing a letter or email to your DM or SM and having everyone in your store sign it. I was in a situation very similar to this and I tried to talk it out with the person and they would not listen. I sent the email to my DM and he instantly jumped on my side and we worked to find a solution. And I’m very happy with the outcome.
That was a lot but if you have questions you can just pm me. Seriously so sorry this is happening to you.

This is straight up abusive behavior. This AM is making the work culture feel unsafe for you and it’s not okay.

I’m sorry you’re dealing with this. I’d definitely speak with the SM and DM.

Report her

This is not okay! You deserve a welcoming work environment that upholds the third place! The third place is for partners just as much as it’s for customers and it’s upsetting that your ASM is treating you all this way. Coaching is one thing, but yelling and scolding is not appropriate. She could have pulled you aside and coached you on not leaving your planted position, nicely. But then to make you cry and then double down is horrible. You should reach out to your SM and DM. If nothing happens from that, file a complaint with partner resources.