Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you with your wee one today.
Now this is never an easy decision to make for our wee ones.
Therefore, at her age and in this situation, it is best to look to her to know if it is time. We need to look at her and ask ourselves if she is enjoying the life she currently has. Is she happy to see you when you come home? Even though she is not keen on walks, can she get up when she needs to (ie go to the toilet, etc)? Can she at least do those things that have made her doggie life worth living all these years? These of course differ for every dog (ie chasing the ball, chewing on toys, sitting on the couch with you, etc) but as long as she can enjoy some of those things that she always has, then it may not yet be time. Of course, if she cannot or if she is caught in a body that won't let her enjoy her life, then we'd need to consider letting her go.
Overall, this is never easy when we are considering the lives of our fuzzy friends. Still, the key here is to look at her and her life. If she is managing with those old age changes (her sight loss, her deafness) and still enjoying these moments, then she may not be ready to leave you (and perhaps you can speak to her vet about a trial on dog safe anti-inflammatories to address any arthritis getting her down on walks). But if it has become a struggle and she is not enjoy her life as she did, then those would be the signs that we need to let her go.
Please take care,