For every person who doesn't really like their mum much, I think there's probably a mum who doesn't like their daughter much.
This idea that mums are responsible for their daughters not liking them, but that daughters even if 55 are not responsible for being a bit horrid, is an odd one, because clearly if being a bit dislikeable was caused by upbringing, then the mum's dislikeability is also caused by her mum, and so on and so forth, back into time.
The best situation is if we can encompass people as they are and not as they wish them to be, but that's the counsel of perfection.
In this situation, I'd just accept she's a prickly person, or that you bring out the prickly side of her.
You are not to blame any more than your mum is to blame that you are the way you are at this stage of the game. She's an adult, she could go to therapy, find ways to interact differently, or get a new attitude, she isn't going to and so the only thing you can adjust is your own behaviour and willingness to put up with it. She probably does care about you a lot of she bothers visiting every week but doesn't know how to show it- perhaps she's an abrupt type of a person, I know a few like this and they are difficult but often mean well.
I would assume good intentions even if she's a bit prickly on the outside, if you reach out to her- thank her for visiting so often, show her some baby photos, buy her a little pressie, and change the dynamic, she may behave quite differently.