bq. I have no idea yet if I can type and talk at the same time

Assume that you can't — I've never seen a presenter who can.

If even you can do it in general, at some point there'll be some kind of glitch (typo, or you're in the wrong directory, or a sample file has already been processed because you did a run-through and forgot to rest them, or ...) which will require your attention to sort out. At which point you stop being able to talk to your audience, and end up stammering intermittent updates while everybody watches your demo go wrong.

Whereas persuading a friend to be ‘keyboard monkey’ and do your typing for you makes things much easier. Because the person typing only has that to concentrate on, they can probably get it right (also, they can follow a written script, something which gets in the way if you're the speaker). But more importantly, if something unexpected happens you can keep the audience engaged and continue speaking while that gets sorted out; you don't even try to help, just concentrate on the audience.

Alternatively, I've also seen recorded demos used to good effect: you make a video screen-capture thingy of doing the demo in advance, then play that out and talk over it. What appears on the screen is exactly what the audience would see with a live demo, but you know it'll definitely work!

Any way, good luck with it.