It's entirely up to you to decide what and how to forgive your mom for childhood trauma/abuse. It's made you who you are and you either do good with that baggage or you do bad...survive and succeed in spite of it. Don't let it be your identity, make it only a part of who you are. Do you say to your mom "I forgive you for x"? would she even accept that or admit she was not the best mom? Only you know that. Is forgiving her for you or for her? Would she actually hear you if you sat her down? Talk to your mom and see how things work out. She may be looking for a way to ask for your forgiveness herself.