Having a connected bank account at 26 is not normal. Just be 100% aware of that. You need to open a new account at a new bank, get your paycheck and all bills connected to that and then close this account. Whether she takes offence or not is not your problem. You also need to get your own phone and own phone bill.

Long term you need to decide if you are willing to financially support your parents. If you get married that will become a joint decision so you need to be thinking long and hard about it now. It is very easy to transfer money to other bank accounts if you need to send her money. Zelle exists literally for this purpose. Your mom doesn't need it, Zelle just sends the money direct to her bank account from yours.