@Former-Member Nelly's age is a guesstimate by the shelter. She was accompanied by two offspring the same size as her, so she was a very young mum with her hands very full. The "kittens" were there, but they were soooo bratty - all over her and not giving her a minute's peace. The staff said she was well and truly ready to be separated from them, and as teen-cats, it was going to be good for them to have their own home space with someone(s) else and relationships with humans.
Part of her being so settled is probably because that experience has matured her, and she now has some space to be herself again, instead of a toy for a couple of wild-child's. The "kittens" were a completely different colour pattern to her (tuxes) so that tells me that's what their father was.
That's all the info that came with her, and the fact that her nature seems to be really placid with no trauma or behavioural problems that they could see, and they had all been there for a couple of months.
I suspect these factors were preventing their adoption - the fact that the kittens matched the size of their mother, and were clearly a complete handful as a pair .... yet they weren't a matching set colour-wise, or behaviourally .... so bringing the whole family home together would have been a real challenge for anybody, and they would probably have needed a large property.
It feels like I have done the right thing to bring her away, and she certainly doesn't seem to be missing them ..... and it will likely get the kittens adopted out quickly now, probably independently too because they are such a handful !!