2.5 is really very early, even for girls. She is clearly not ready. Don't worry about the stories you hear from people whose kids trained at 12 months or 24 months or whatever. Every kid does things at a different age. If yours isn't potty training, her brain and body development are in another area. It all evens out by the time they are 5, 6, 7! My child was very late to potty train, talk, and give up napping. However, he was extremely early in creativity and gross motor skills like walking & running.
Pushing it too early will turn into a lot of nagging, cleaning up, frustration, and anger, and may cause resistance later. Put her back in diapers, put a little potty in the bathroom so she can see it, and just wait. YOu can get some books on the subject, but just read them on occasion and very non-judgmentally, saying, "when you're older, you'll do this." Same as "when you're older, you can go to school."
Concentrate on all the things she IS doing well, and just enjoy her childhood. Other than the expense of diapers, what's the rush? It's nice to get them out of diapers in some ways, but then you will be glued to store bathrooms and constant rushes to find a potty when she needs one! Don't worry - everything has an up side and a down side.