C.W.
You know what, don't stress about it and don't let anyone tell you she should be getting it by now. Every child is different!!!! If she's not telling you she needs to go pee until after she's already done it, it doesn't sound like she's getting the concept yet. Will she go to kindergarten in diapers...no, she will when she's ready. My twins were closer to 4, we tried it earlier and every time they didn't get it and it was horrible, finally I waited until they really seemed to get the concept and boom they totally did it. Hardly any accidents, no problems at night ever, so wait awhile and try again.