AITAH for not knowing that a female sparring partner in my grappling class had a neck fusion?

I sparred with this girl tonight in my bjj class, before we sparred, i even offered to show her a trick on my favorite takedown. as we began i realized she was ALOT stronger than i thought she would be, naturally i put a bit more pressure on her. we went almost five minutes in two rounds. the first round she tapped me. The second round, i tapped her with a standing guillotine. She basically gave it to me. She got mad and had a mouthguard in. She said something to me that sounded like "i tapped". i apologized, thinking that she thought i held it to long, but I DID let go as soon as I felt the tap. at the end of the class, the coach reminded everyone that she had a neck fusion and looked right at me and said my name. This is the first time i can remember hearing about this. I even thought about it and tried to remember if i had known about this before. I mean, she typically goes to the boxing and women's self-defense (lol, it's free too), and i have rarely seen her in the grappling. I apologized again understanding my mistake, which she acknowledged. My coach drives me down a couple miles to the bus stop as usual, and during the whole ride, proceeds to berate me about this, telling me i could have cost him one of his only female students. I kept reiterating that i didn't know she had neck issues, I truly don't remember knowing about it before. He then says that she told me before we sparred. She did not. He didn't relent and kept defending her saying she told him that she did tell me. After I wouldn't back down about not knowing, he switched his accusations to she tapped me, so i decided to get revenge. What the fuck is that even? This guy has known me since 2013, and knows i have never acted in that manner. Well a girl embarrassed me, he tells me. I have sparred with three other girls that were formally at the gym, and never "decided to get revenge" for being embarrassed. So, AITAH?

I know i should have written this in paragraphs, so here is the second one.

Also, I have been disabled since birth with Spina Bifida, it is substantially more noticeable than a neck fusion.