1st time OP so go gentle.
Eldest DC is 14. She is almost always aggressive and selfish. This has been going on for about 8 years as she is desperate to be independent of me.
Generally I try to rise above but every now and then (like today) I lose it and assert that I will not be treated like this. DH generally takes her side / keeps the peace.
Just need some reassurance and advice as I am learning on the job here.
Background I've just spent about £500 (which we can't afford) redecorating her room, new bed, duvet cover, blind, printer(!) hence my frustration...