Is it best for me to be on her bank account jointly now?

Need some more information, as to why you need to be on your mom's bank account? Do you feel like the Executor won't be able to handle her affairs after she dies, because he is too far away? Then you should definitely try to have the check writing privileges after she dies--if that means you need to be joint on her account I don't see how that is benefitting or conflict of the POA. The bank can have their paperwork signed or witnessed in the hospital without the POA being in the room, if the mom wants to sign it or otherwise indicate her decision to do so. Is her funeral pre-paid, or will this be a need?

She would have to be well enough to go with you to the bank and sign the papers. A POA cannot execute a document that would benefit himself. Plus if mom is on Medicaid, benefits would screech to a halt immediately.

I'm confused, you say you're POA on her bank account....but are you named as a "joint owner" on the bank account? that is a big difference. If the bank recognizes you as POA for signing checks, that is not automatically the same as being a "joint owner". IF possible get her to make you joint owner, then the money will be yours the instant she passes, and it does not become part of her estate.

True as cmagnum says. POA is void when parent dies and joint holder of bank account becomes owner of bank account when parent dies. The account is no longer part of your parent's estate.

As your mom's durable POA, you can pay her bills from her account without your name having to be on it. However, if your mother added your name to her account then she must want that money to go to you when she dies. Have you ever seen the will? Where does the executor of the estate live? What is your relationship with him like?