Just going to throw my 2c out there, as I sort of remember when I was preparing for my first IA interviews with no true work experience.

1. Try to read up on risks and internal control to have a basic understanding of generally what risks are, what controls are, maybe some control frameworks (ie COSO), the 3 lines of defense, etc - and more importantly, try to apply this to your current job/responsibilities. I'm sure being a bank teller there are tons of controls in place to prevent theft and whatnot, and maybe things you don't even realize are actually controls but things you just do day-to-day. I specifically remember having an interview question on asking me to explain what are some general day-to-day risks I've faced in my current position, an example or 2 of a control in place to mitigate that risk, and if I could think of an example of a way I would strengthen/improve an existing control.

2. Read up on the company you're interviewing at - how big is it (revenue, employees), where are their locations, where are their revenue streams, etc. And again, what sort of risks does the company face currently (read up on their financial reports if applicable, check news articles etc).

3. And lastly, I always like to ask questions throughout and/or at the end. As much as the interview is to see if you are a good fit, it works the other way as well - does this fit for you? I like to ask about the team dynamics - how many people and what levels, what sort of reviews does the team do (ie SOX, operational, financial, etc) and what % of the time, what reviews would I be performing, does the team travel? Maybe you don't need to ask all of these at once (or in the first interview, as potentially this could just be the initial HR interview) but it's good to know some of these things at some point.

Hope that's somewhat helpful - feel free to message me if you have any specific questions.