I am mom to a 10.5 year old dd.
Hi, and welcome
Wow, you have your hands full. I would
A child may HAVE ADHD, but it is not what they ARE. Never tell a child they ARE ADHD.
By all means, get her assessed for ADHD, but like the PP suggested, firm rules and boundaries are a good idea, and likely what would be suggested by a counselor/pdoc/ped. as a remedy for the kicking off. Personally I'm seeing (and I acknowledge that I have been given very limited info) a lot of behavioural stuff from your post (so, not so much ADHD, but kicking off because she currently ends up getting her own way when she does).
I have to say, BTDT, but in my sitch it was me feeling guilt from having pulled him from public school (where he wanted to stay) to homeschool him. Because of the guilt that I was feeling, I was taking a lot of cr@p from him. I had to get tough to get it back to "normal" levels of (tween) cr@p (LOL). It's much better now (no more screaming abuse at me, or emotional manipulation), but I still have to sometimes lay down the law and let him know that showing respect is non-negotiable.