Why is it so difficult to forget and forgive something which happened three years ago ?
Why there is a need to look for hidden meanings and hidden agenda ?
If there is a hidden meaning and hidden agenda it will come to light if your mom forgives and forgets otherwise it can be a new beginning of a lifetime friendship with a desperate woman who wants to build bridges and start a fresh.
Go for it and get rewarded by Allah(SWT) who loves to forgive.