@Worried1305
You probably don't mean any offence, but I would be quite offended if it was me, and I would refuse.
Some 15 years back, in my old area, a woman who lived in my street (on the opposite side of the road, some 3-4 houses down,) was having a 30th birthday party in her house. She had invited around 42 people, including work colleagues, family, a few friends, and about 10 neighbours, (2 of them who were either side of me,) and had not invited me/my DH/our 2 kids. She even said to me (the day before) 'it's my birthday party tomorrow night, so apologies in advance for any noise or rabble rousing! There will be over 40 people coming.' I said 'errr ok...' and walked off.
Just 15 people turned up. Only 3 of the neighbours, 3 colleagues, 1 friend, and 8 family members. An hour into it, (as I was cooking our evening meal,) she knocked on our door and asked if we all want to go. DH answered and came and said 'Lynne from across the road asked if we want to go to her 30th birthday party. Do you wanna go?' I said 'No I fucking don't. What, she asks us an HOUR in to the party, she has some brass neck, I'll give her that.'
He went back and said 'no thanks, we're good. Bit late now and we have our evening meal almost ready.' She went very red and said 'I heard what Maybug said, I hope I haven't caused offence.' DH said 'well, not inviting us at all, and then asking us an hour after the party has started is pretty poor form to be honest. It's an afterthought.' She just walked off sheepishly. (We found out next day that only a third of the people invited had turned up.)
It was a few weeks before I saw her again (to speak to,) and I just spoke to her like nothing had happened. It was never mentioned again.
tl;dr yeah @Worried1305 don't invite this woman. Being an afterthought, is a bit worse than not being invited at all. 'Errr, so the people we REALLY wanted to come are not coming, so we want YOU to come to make up the numbers.' Fuck that!