I am an undergrad, but I have a question about academic etuiquette. Is it appropriate to ask it here (or even on the main forum)? I'm not sure if academia.SE is only geared toward the grad+ level.

@UnderMathUate academia.stackexchange.com/help/on-topic is the place to read about what is appropriate to ask here, though it's fine to ask clarifying questions as the guidelines are subject to interpretations based on discussions on Meta. Undergraduate admissions and undergraduate life and culture are explicitly off-topic.

You should look to see if someone else has asked a similar question first, such as academia.stackexchange.com/questions/90725/…

And also see the tag academia.stackexchange.com/questions/tagged/etiquette and perhaps search in that tag to narrow things down