I potty trained DS2.5 about 4 months ago and he caught on immediately. I would however have to take him since he would deny he had to go. I took a couple of months for him to start telling us. I think early on they are just too "busy" to keep track and want to take the initiative to go. I'd say keep taking her and eventually she will lead. I am sure within a couple of months she will be telling you.