Redecorating DD's room, paint and/or wallpaper?

[NotAnotheChinHair]

Hello. A bit clueless here so perhaps someone could help me. DD's room is well overdue a redecoration. DD is 10 YO and not very girl, so butterflies and pink are out of the question.

I was thinking that perhaps it might be nice to have metallic wallpaper on one of the walls but all I have been able to find looks too adult-like. Is this a bad idea anyway?

I am an avid pinterest user but in this occasion it is not helping me.

Should I paint the room one colour, then one small wall (ie the one with the fireplace) a different colour and use lots of metallic decals? My DD will appreciate things like birds and feathers (a slight boho vibe).

Anyone know a good online shop for good quality decals? What about wallpaper?

Thank you!

My DD is 11 and we have recently repainted her room in a turquoise colour as she too wanted to ditch the pink girly look. She has white furniture and light wood flooring so the room can take any colour combo on the wall without it being too overpowering.....
I prefer paint as it is likely she will want different colours again as she goes through the teenage years, and it is easier to repaint rather than remove wallpaper etc.
We haven't put up any decals - she has a load of posters instead!
HTH