Potty training

Anyone's kid potty trained? My daughter will be 3 in a couple of months. And shes not getting it. I really wanted her potty trained before her third birthday. My sister in law has a kid that is 6 months younger than my kid and her kid is potty trained. I asked her if she needed to go and she said no. Then not even a minute later she peed herself all over the floor. This has happened multiple times. We ask her and she says no and then she has an accident. We do underwear during the day, thin ones so that if she goes she feels wet and hates it. She ran to the bathroom afterwards. I just dont know what to do. We give her treats after sitting on the potty if she goes. She knows where to go. Im just getting frustrated. This is day 3 of this. Day 3 and shes only gone 2 times in the potty.