Hey, I've made plans with a girl, we agreed on time and place, everything went smooth as a butter.

We are meeting tomorrow, but after settling on plans she texts me, if it's possible to hang out a day after tomorrow. She didn't brought that up when i first texted her, she straight up agreed. I told her, that i'm not available saturday, but it is more of an logistic issue for me. she then texted that we are maybe good for tomorrow. Did I screw up not being flexible?

Edit: added details.