Found myself at a rehearsal room last night that didn't have backline. Dug out my battered BDI21 from the bottom of my bag, plugged DI into the PA.
Worked a charm, sounded good to my ears.
I've sometimes thought about a cheap, headless, stick bass to have as backup. Small and light package to load and store on stage.
Something like this
Has anyone taken that approach?
My view is that if you want to and it makes you feel more confident (not necessarily younger looking) then go for it.
You clearly want the gig so I wish you the very best of luck.
I'd love to hear how it went.