Did you receive any of the proceeds? Did you have any 'control' of the home?
If you were merely put on the title and had no authority or control of your home (your mom treated it as fully her own and she received all of the proceeds), it sounds like an Implied Life Estate.
*IF* that is the case, your taxable amount probably isn't what the 1099-S shows. As a "remainderman", your ownership is based on the Actuarial Tables that are partly based on your mom's age. I recommend going to a tax professional to handle this.
