Finally got hired as a legal assistant... I'm so nervous

I've (38M) worked in the bar/restaurant industry my entire adult life, for many years as a bartender, and most recently as a restaurant manager. I have a B.A. in English, and last year I started an ABA approved paralegal certification program at UCR. I'll finish the program in May, so for the last few months I've applied to every entry level legal assistant job i saw post for on indeed. I had a couple interviews and finally landed a job with a plaintiff side labor/wage law firm as a legal assistant. They're obviously aware I have no experience, but as my start date nears I find myself starting to doubt that I'm actually capable of this... it seems so intimidating. Also, having worked in bars my whole life, shifting to a "professional" office setting seems daunting. How do I dress, what do I say? Lol Not to mention, I'm taking a massive pay cut, and will need to bartend a couple nights a week just to supplement my income, while still attending my paralegal courses. I guess I'm just venting, and also looking for some insight or advice from someone in the field to calm my nerves. I appreciate it!