Judges and Grudges

I have recently come to the realization that I am a hypocrite. I hate to say it, but it is true. Two things I cannot stand at all. Judges and grudges. Two things I am terrible about. Judging people and holding grudges against people. How did I go so long without realizing how double standard that is?
I'm not going to lie. I met someone a really long time ago and did not like her. But we were both immature and stupid. I judged her based on things she said and did that annoyed me, and decided i despised her. Then she came to my school and still holding on the those judgments, I refused to be her friend. I know. It's terrible. Anyways, since no one really liked her in the one year she attended our school, she didn't come back the next year, so i didn't see her much. When I saw her at youth every now and then I just tried to avoid her as much as possible.
Once though, she approached me and said she wanted to start over. She wanted to forget the past and be my friend. Problem was, I didn't really want to be her friend. But I was willing to forgive her, and apologize for my wrong doing. So that was that and the past was the past. The next week when I saw her she came up and was being all buddy buddy with me. I smiled and acted nice, but in my head I was asking myself why the heck she was acting like she was my best friend. Oh right. Because she actually did forget what happened. She let go of her judgments and if she was holding any grudges, she got rid of them. But I hadn't.
She stopped coming to youth every week and I really didn't see her much at all anymore. So i gradually forgot about all that had gone on between us. Then, recently, she was in the same play as me. From the second she walked in I was annoyed with her. Her voice annoyed me, her mannerism annoyed me, the fact that she got the part i wanted annoyed me. But when I was talking about it to someone, I stated that I couldn't really pin point what was wrong with her. But now I know.
Even though I can't even remember why I used to dislike her so much, somewhere in my heart and brain, I still do. I still judge everything she does based on how immature we were when we first met. But that is so unfair and I know it. People change and grow up. That I am positive of. Because the mother of one of my friends actually dislikes me for something I did years ago. She stated once to her daughter that she didn't want to have someone that she didn't even like in her home. That someone was me. And it made me feel absolutely terrible. So then, how terrible must it make this girl feel when I am constantly cold towards her and rude when she has put in every effort to make things right?
I want to be nicer to her. And I am going to work on it. I am going to pray and ask God to help me find a way to dig deep and forgive and forget everything. Because she doesn't deserve to be treated that way and I know it. And there is nothing worse than knowing your hurting someone for no reason and continuing to do it.