Is it okay to let your mother back in your life, if she abandoned you at a young age?

Today I got a call from my mother. She said that she wanted to get to know me again. This coming from the women who left me at age 6 with my dad, then came back 8 years later to fight for custody. I turned 18 before, she won. But my sister went with her. It broke my dad's heart and he started drinking. Basically I blame all the bad things in my life on her. She's not totally blameless though. So now she wants to come back in my life. So should I let her?