Well, aren't you sort of her students? Of course, some people are just annoying like that. She might just be that kind of person that thinks she knows best at all times. Or, maybe there really is a purpose for her treating the assistants like students. Maybe there's still things you all need to learn.
I haven't met her, so I can't tell.
I used to get really annoyed by people lecturing me or treating me as a kid(or student). But now I've learnt do differentiate between the ones that are just jerks, and the ones who are really just trying to be helpful.
My boss is the kind of person who thinks he knows best. Each time someone comes and ask me a question at work, even if I've already began to answer, he will jump in between and answer that question a little louder.
Or he starts lecturing me on how to do very simple things, no matter if I say that "I know how to build a box", he will keep on "teaching" me about it. That's just rude, and indicates self-entitlement. Worst thing about it is that he's actually really dumb, and I have to keep myself from explaining things to him all the time XD
My boyfriend is very welcome to lecture me, because he doesn't do it because he wants to feel superior. but because I really don't understand certain things. I can still get pissed about it, because I want to handle everything myself, but eventually I can see that he's just being helpful.
Like when he helped me fix the flat on my bike. I felt like I was being treated as a child, and didn't want his help. But now I'm really glad that he did it because he really is better than me at that stuff.
Or when he let me know that I shouldn't talk loudly about sex in the supermarket. At the time I was like "Don't tell me what to do!", but I realize now that some discussions are not meant for public places.
So, is that teacher really just trying to be nice? In that case, start welcoming the help she offers you.
And if she just has a superiority-issue, it's not the worst thing to just take it when you need to, and laugh it off later.
I don't like back-talking, but complaining about my boss to my co-worker is an exception. It's a lot of fun.