I'm stretching myself, switching from blues to heavy metal, learning fast picking. I'm good enough to play Muse, but not good enough to play The Color Black by Dayseeker without a lot of practice.
I have the opportunity to play with a metal band. I have a recording of the set and with a lot of practice can do a decent job probably.. but they today asked me if I'd come in for a sit-in practice and I just think that I'd embarrass myself I'm not prepared. I was going to learn their songs but then set them aside to learn the Dayseeker song.
I've done this before. Said that I was better than I was and just worked really hard behind the scenes. Harder than anyone realized. And it's such short notice. I'm thinking that I'm just busy today.
But if a sit in practice comes with very low expectation, then maybe I should go?
I think that most everyone at some point in their development as a bass player has gone for an audition that was a stretch for their current ability level. The most important thing, IMO, is that you make the band sound good even if you have to simplify a bar or two to play cleanly and with precision.
Approach it like a pro...chart the music (in whatever complicated or simplified manner makes sense to you) so that you have a map for all the songs' structures and can hit the stops and starts, practice the songs so that you can play them clean/in time/with the right feel, and show up prepared like a pro even if you are early on in your bass journey.
If they don't give you enough time to prepare before hand, then take a notebook with you so you can create your charts in real time. Don't be afraid to ask them "how many times does it repeat the intro bars before the verse? How many bars is the guitar solo? Can you show me that riff where the bass doubles the guitar?" etc etc. Doing this shows that you have a systematic approach to learning/mastering the songs even if you don't know them at the moment.
Lastly, for that volume of music, take earplugs for God's sake.