... when hers looks like this?
DD is 13 and has a desk in her room but it is just covered in crap and is never used as a desk. It's more of a glorified shelf. She will however then insist on using the desk in my room! The fact she has her own desk has been explained to her but I still get pouted and huffed at when I tell her she can't use the room (not all the time but I'm not being kicked out of my own bedroom).
So WIBU to bag up the stuff that's on her desk and remove her desk entirely? I think I'd hide it in the shed temporarily to make a point. I could be verging on the petty but it's really getting under my skin. The rest of her room is ok(ish) it's just her desk that is left in this state.