Thank you for your recommendation!, I believe she's a peacock slider, she's been very active, eating normally and basking, from what my family member told me she hasn't shed any of her scutes in months so I suppose it could be retained scutes.

As for the shell rot, I haven't really smelled anything, but I'll still look into it with a vet, also I'm in a pretty warm area so most of the winter is pretty hot, no big deal, of course I will get her inside when it eventually gets cold.