How do I respond to my mom resurfacing after 4 years?

My mom left when I was 13. She just disappeared one day leaving only a note behind. My dad has been really great. He is there for me all the time in everyway he can be and I owe him a lot. Now that my mom is back a part of me wants to see and talk to her but one I feel like this betrays my dad who has been increbile in the face of all this and two the other part of me isn’t sure that I want to see her. I have spent the last 4 years trying to be perfect and part of that was in the hopes that she would come back and see how good I can be. I don’t know what to do or how to handle this.