You have several options. 1) You can keep paying. The contract probably says that you will be in default if there are any changes in the people who signed for the loan. Therefore, the bank may be owed the entire payoff. On the other hand, the bank is not going to come after you while the note is up to date. 2) You can refinance the loan and put it in your name. If you have bad credit, obviously, there may be an issue. You would need to clean up your credit as quickly as possible. You did not say how long you had left to pay on the loan. You should have reduced the mortgage and the home hopefully has appreciated. The bank may loan you the money even with less than great credit. Of course, once they know about your mom, the bank will want something done to make sure it can get its money if you fail to pay. Be careful.
If you continue to make the monthly payments then you should be fine. The better option stated by Attorney Moskos would be to see if you can refinance and pout it in your name. If the mortgage was taken out 13 years age, then you would benefit by today’s lower interest rates.
Good luck.