Sounds like a fun time! Just relax you will do fine.
Do you have a front internal mp2 kit? That would be the easiest to do. I would suggest the following.
Just have the bike on the kickstand, have the brake levers, throttle, and control buttons already done. Then explain to people how you removed the old grips with a knife and brake levers by loosening a couple of screws. Then you added the new Items by "just slide them on and tighten them up"
Have someone help you flip the bike over. Take the old wheel off and put the new one on . Might want to have an exta tube and tire on the new one already and explain how you can just transfer the tire and tube you have already.
Have a loose battery on hand and just sit it in front with a long battery cable. Plug everything in and give it a couple slow spinups.
Of course you need to practice this a few times first, but you should be fine.
Because I'm sure you all agree, a girl couldn't possibly know enough about this stuff to command respect from this audience
Also I think you are looking at this wrong. If I had a choice of watching a girl or a guy demostrate an ebike build, well .....
hmm, I better not say, but I think you know what I'm saying
Gary