As an MS1, you won't be expected to know much clinically. In line with your level, I would recommend really reading up on head and neck anatomy. Use whatever text book your anatomy class requires. I liked Moore's "Clinically Oriented Anatomy" since the anatomy is presented with relevance to clinical medicine.
I wouldn't get ahead of yourself just yet. You should read more anatomy and start shadowing. If you end up falling in love with ENT, then get
neck deep into it...start doing research and reading more focused literature. If I were you, I wouldn't read ENT Secrets. It's too advanced for an MS1, in my opinion. Plus it's not organized. Try something like the Washington University Otolaryngology Survival Guide if you want to get more in depth. It's (1)organized and (2)pretty basic.
Congrats on the initial contact.
Keep the questions coming.....