Good advice from Pennydesign about letting it dry for a bit before trimming. I wish I’d known that before my first wallpaper project! Don’t be nervous. Unlike paint, wallpaper can be shifted and adjusted before you smooth it down, so it’s very forgiving. Also, since you’re doing a small area, you’ll probably have some extra paper in case you have to redo a piece. Take your time. You’ll learn as you go, and I bet it will be beautiful.

wallpaper would look nice

Please share photos of the wallpaper and room. Hard to say for sure without visualizing the actual elements.

Are the mirror and those scoances staying? I would do the whole space but I have really no clue as to your style . You will need to address the lighting before choosing wall paper and I see a very modern toilet but with the mirror and sconces not at all that style. I need info.