Okay this isn't pregnancy related but idk just need someone opinions,

Okay this isn't pregnancy related but idk just need someone opinions,

So I take my fiances niece to school when she's here every other week, so lately she had been bugging me and telling me that her mom(my sister in law), said that I HAVE to take her to school at 8, well she didn't start school till 8:45 like she'd get to the point that she would knock on the door multiple times before it was even 8, sometimes my fiance wasn't even home with the car for me to take her. Well anyways yesterday I finally asked my sister in law why she keeps on saying that and she said oh its probably cause she wants to go early to play, and of course I got mad like I'm over here thinking it's important and she's been lying to me this whole time, so today I talked to her and told her that I'm not taking at the time she wants to, especially since she lied to me, maybe I overreacted or something but that really bugs me like she was trying to see what she could get away with me and its like really bugging me, I kind of feel bad but I know that if wouldn't have put my foot down she would still be trying to see what else she can get away with.