Dog on bed

I have a rescue dog (four yr old F (suspected) Finnish laphund I've had her for about a week now) she resource guards (both bed and food) she has recently (just today) started sleeping in my bed, she slept next to me for a few minutes she has a startle reflex when she sleeps (which I wasn't told about) and bit me ( it scared me more than it hurt me but it did leave a mark) I sent her out of the room ( she's very obedient) and waited for a few minutes before I interacted with her, I made the decision not to let her sleep in the bed with me yet for safety reason. Just a little bit ago I was heading to bed and was telling her 'off' ( from just outside the room, calling her name gently, ) we then proceeded to have a long session of bared teeth growling and snarling that I stood my ground through and she eventually stopped dropping her head and moving off the bed and into another room where I was pointing (she has a xl crate in there and that was where I wanted her to go, but I'm working on that) she came over later doing the " oh hi you're here" butt wiggles with a lowered head I gave her some pats and she tried to come back up again and I sent her away towards her crate.

What I want to know is: if it was a good decision to let her sleep on my bed while I'm not in it ( I feel like I shouldn't, but that it also a good opportunity to show her that I won't back down when she growls at me even though she does generally listen when I tell her to ' stop' and 'leave it' as well as I good opportunity to show her she needs to listen to me)

Is it a good idea to show her that her growling, snarling and lunging don't scare me?

Or should I just make my room a "restricted area" and keep the door closed when I'm not there ( I can't sleep with it closed as I have some PTSD)?

I want to also add she has other beds

She use to be beaten and kicked a lot by her previous owner and made to sleep outside tied to a clothes line, so she use to being alone and not near people all the time ( she won't wear collars or leads now because of it) even segregated herself off from her foster carers as well

She is a good dogs and it's early days yet, most things I've figured out on my own but I want opinions on what I should do.

I'm trying to tackle one hurdle at a time… And there's a lot of them.