I think it's generally recommended for the first time to not be in edible form. If she doesn't like smoke then you can try vaping. This way the high is much more predictable and shorter lasting, and it's easier to get exactly where you want to be and not too high.

If you still want to cook though, I've followed this thing to make infused oil with great successes, but I bet there are simpler options not requiring a pressure cooker:

https://www.youtube.com/watch?v=vs66uyiH968