Age has nothing to do with it.
Is she ready? Is she interested when you go? WIll she sit on her potty (with or without clothes) for a couple of minutes?
If she is ready, then let her run around without pants one day. Keep a potty nearby and get her to it when you see her start to go. Once she realizes that she's supposed to do THAT in the POTTY, you are on your way. Switch her to panties except when she's asleep, take her to the potty at regular times or when she starts "dancing", and treat accidents as simple accidents.
If she isn't ready, you can start taking her to the potty at set times and holding her there. If she fights you, stop. You will only make things worse. If she sits there, leave her there for a couple of minutes. After a few actual success, she will start to realize what she's suppposed to be doing. This may take months depending on how "un-ready" she is. Then proceed as above.
at 8:16 PM on Jan. 12, 2009