I’m 80. I love both my daughters to bits, and got on fine with them, but don’t want them to live with me. I like to be free to do what I want when I want.
When I had my hip replacement the daughter who lives near me kept popping in, and fussing around me. “Let me do that. Be careful. Are you ok? Do you need anything?” I was grateful for her help, but felt smothered by the attention. I was glad when things got back to normal again.
I’m glad that you got out of your bad relationship, and your Mum will be glad to take you in until you sort yourself out, but she may not want, or need you as a permanent resident. Talk things over with her, and be prepared for a change of heart from either of you. Finding accommodation nearby may be a better option, and perhaps you could then reclaim your dog, which I’m sure you must miss.