I remember what I did when I was completely green at tiling. I'd been at it for like two weeks at the time, and while measuring out a splashback at a site, the builder came around and started chatting. He asked me how long I'd been tiling for, and I put on a dead serious face and answered "two weeks". Poor sod looked aghast, and I started laughing. He started laughing too, and said "good one mate, aren't you the joker?". He patted my shoulder and left, chuckling on the way out
I became his "contact person" among the tilers, and he never gave me any trouble
Anyways.
If you prepare, and handle yourself well enough, no one might even think to ask you uncomfortable questions regarding your experience.
Take your time, and plan properly, so that you don't have to improvize, because that is where inexperience shows. Read up on things you know you're going to get asked about well ahead of time, so that you don't have to think or hesitate about the answer. Study things you know you're going to be asked to do, so that you know what to expect, and what misstakes to avoid.
Adopt a professional attitude. Answering "I'm on it" just to show your mettle when asked to do something which is completely insane is the opposite of professionalism in my humble opinion.
That's all the advice I can give you.