I was in the middle of rotations when I got my first interview invite; I was on cloud nine the rest of the day, haha (the only feeling that surpassed that was when I actually matched--I'm excited to see everyone's reactions when that time comes! It's going to feel like forever until then, though!)
From my experiences and from what my RPD and preceptors have said, interviews are a lot about seeing how well you fit in the program. It's a nerve-wracking experience, but the programs where you're the least nervous and where you get along really well with the people end up being where you do the best, regardless of how well you prepare your answers. My program in particular was looking for personality on the interview day, since on paper most people look the same.
I'd definitely look into those 'common residency interview question' documents online and come up with scenarios for the major ones. Only a few programs deviated from those types of questions, and you can tailor your answers to other questions to make them fit the weird questions sometimes.