She will message and ask if I’ve got visitors whenever I have people round. I feel watched every time I pass her house. Am I being paranoid or is she over stepping boundaries?
Yeah, it's pretty intrusive, but gregarious, highly extroverted people might not agree.
Messaging to ask if you have visitors when she can see you have visitors is an obvious hint to be included - reads like you are abe to resist that one but there is ALWAYS the option of not responding to bloody stupid text questions.
Coming in without knocking all the time is definitely over-stepping, but locking your door isn't a viable solution to the thick-skinnned - telling them your feelings, & that you 'do visiting differently', is.
I’m at the end of my tether and I think she’s under the impression she can come over when the baby arrives and she insisted at one point to be my birthing partner but I told her I don’t have a birthing plan yet.
That anwer is only putting off the inevitable though isn't?
"How kind of you to offer but no thanks, my plans are already made."
"There's no need to discuss it, I have people in place already."
"I'm going to be spending a lot of time as a family-only unit, bonding with the baby"
- are all answers which would work better. Just keep repeating them if she goes on about what HER plans for the birth are! It's called 'The Broken Record' technique & it works if you stick at it.
Ignoring her for months hasn’t deterred her, so what else can I do?
Some people pick up on minor social cues.
Some people do not. We know which one she is, so of course ignoring the situation is not going to work. You have to use your words. "Lovely to see you but I've got plans now so see you another day" - "Pop round in the afternoon but only til 3pm 'cos I'll be sorting out DC's [whatever] then" or even "I'm having quiet time today, but can see you on Thursday morning" etc.
In short, you have to re-educate her that visiting is by pre-arrangement, & that you do not hold an open house.
Good luck, & good luck with your ACTUAL birthing plans, when you have them!