I’ll echo what some others said about Portal, but here’s a handful of games that I’ve enjoyed for their comedic value:

What the Golf is pretty funny if you like/hate mini golf.

Many of the LEGO games have some good humor: Star Wars is my favorite, but LEGO City Undercover was fantastic, too.

Borderlands 2 has some great comedy, with The Pre-Sequel as a decent runner up.

The Yakuza games are fantastic; I recommend Yakuza Kiwami for a low-cost entry that allows you to dip your toes in and get the feel for it

Untitled Goose Game is funny because you make it funny.

I haven’t beat 3, but I have beat 4 and 5. I think 5 took the good parts of 3 and 4 and put them in one game. If you want her to play all of them, I’d suggest start with 3 and move her way up. If you want her to get hooked right away, I’d probably say 5 Royal.

And don’t forget Metaphor in the list!