Step mom issue's would you let it go?? Little long.

Ok this goes back about 3 month's, it was the first week of September. My birthday was September 6th; I get a call from my step mom offering to watch my kid's if me, my dad n bf wanted to go to bingo or the casino. I got off the phone and started talking to my bf and I mentioned going to red hawk(it's a casino). I call my dad back and asked if he wanted to go there, he told me if I wanted to that's fine. Later that night I get a call from her saying they got into a big fight and that he left I didn't know what the fight was about till the next day. My grandma told me the reason they fought is because she told him we were only ALLOWED to go to one of the place's she said or she wasn't gonna watch my kid's because red hawk is a place she likes and if she can't go no one will. That pissed me off and I confronted my dad about it, he said it's true and that's why they fought.

Little back ground about her... She is the type to think her shit don't stink, her opinion is the only one that matter's, if it pisses her off don't do it, you can't joke, laugh or point a finger at her but she can do it to you. I've seen her at her worse and the way she treat's my dad is shit!! I've always held my word's for my dad.

Back to the story...This just topped it for me I told my dad I don't want her offering to watch them anymore and that I don't want anything to do with her. One thing people don't know about me is if it involves my babies in a negative way you are on my shit list. She used them against us to get what she wanted and you wanna know what really got me? My dad took her to red hawk the weekend we were suppose to go. It's been 3 month's and I haven't talked to or seen her, People say let it go for my dad's sake; but it Hurt's because she claimed to love them, my son call's her grandma, she was in the room when I gave birth to my daughter. Then she turn's around and uses them as a pawn to get what she wanted! People don't care about my feeling's and make it seem like what she did was ok. My dad only see's them when i take them to his work; he asked me last week to bring them to his house because it was my son's birthday but we all got sick. Now this week he asked to bring them up so we could carve Pumpkin's, I really don't want too but I am because my son wants to see him. I want to let it go but I just think about what she did and what my dad did and it fuel's the fire again!!

Should I let it go? Should I talk to her?! Was I wrong for getting upset?