Finally landing some interviews. (wells Fargo Middle Market Banking).. need advice

So I transferred to my university (solid private but non target), from a big public school earlier this year, switching from Engineering to Finance + Math. My GPA is good, but I was having trouble landing internships probably due to lack of experience since I haven't worked or interned in finance at all before.

Through extensive networking with alumni, networking events, getting my resume reviewed, etc... finally started hearing back.

I just got a first round interview, scheduled in a couple of weeks. To be honest, I've focused almost entirely on applying for internships not preparing for interviews, where do I get started, and what information can I chug to ace this interview? I saw the WSO Technical Guide which I am studying the hell out of, and going through questions on glassdoor... what else should I do?

For a dude who just transferred to finance, is this a decent position? I know I'm not at a bulge bracket or something, but would this be a decent start to my career if I could land it?

Thank you