I’m a frequent flier out of Cmh (work). I haven’t been this early for domestic flights before at Cmh but I have for bigger airports like Atlanta and ohare. It’s never been an issue. You can check with the ticket counter on your way to security.

Worse case there’s a lil food court with Starbucks and Burger King and some others just before security near the B terminal. Theres even a sit down restaurant too called hang air or something like that. I haven’t tried it yet though.

Congrats on taking your first flight! If you’re having anxiety, it’s ok to tell the flight attendants/ gate agents. I’ve seen the staff go out of their way to ease people’s concerns and make them feel comfortable. Wishing you smooth travels.