My mother lives in Independent Living. She refuses to move to AL (same building). How do I make her realize I can't be her sole caregiver?

Good that she agreed. I would think eventually that the complex would recommend AL when they were made aware of any decline.
You are not independent when you need to rely on others to do things for you.

Wow, that turn around happened before I could type a single letter 😁!

Maybe you have a lovely sweet natured Mother who can see the sense of it & doesn't wish to burden you.

Your beautiful positive nature shines through with the mention of 'a fresh start'. I love it.

Blessings to you both for this new chapter 🤗🤗

Thank you I have been trying to do less today she agreed to move and says she thinks she will like it. She just so lonely since my dad died 2 yrs ago they were married 70 years. Told her she going to have a new start ( at 90 yrs old )

Stop doing for her & she will realize, in short order, that she needs more help. As long as you keep doing all the care giving for her, why should she move to Assisted Living?

Good luck!