If you've always had good luck with this garage you should have nothing to worry about, right?
I've never been to a garage before besides things like tires that I don't own the equipment to do myself, I don't personally trust other people to care for my vehicle as if it was their own, plus I can't afford it, shops cost so much lol. I'm also a firm believer of "if you want something done right, do it yourself". But if you have used these guys a bunch of times in the past and have and been happy with the results, why would this time be different? They might be backed up now, but hey it is what it is. Don't worry, if these are people you trust then you shouldn't sweat. If you don't trust them, why bring it there in the first place?
Yes you should chill. It's Friday night, enjoy yourself.
If you don't mind me asking, what are you having them do to it?