21 months and starting potty training.
We have had a potty for a while and he has continually told us when he is having a wee or poo. He likes playing with this fancy lightening McQueen potty pulling the handle that makes a flushing noise like a racing car and taking the ring and placing it on his head. He liked to sit on it too. We bought Bob the builder easy up pants and this encouraged him. He had a few days successful potty experiences and a few mishaps and then he got tonsilitis and it seems to have put him off going on the potty.
So we bought a simple potty and even stuck a 'nemo like' sticker on the potty to make it more attractive. He still doesn't want to go on it! I don't know how people do it. He must not be ready.