Potty training varies with the kid. When my daughter was about 8 months old, I put her in a swim suit (prior to swim diapers) and I told her "you can't potty in your swimsuit". She told me every time she wanted to potty. So I bought some minnie mouse panties and said "you can't potty in your minnie mouse panties." And she didn't. She was SO tiny, and insisted on using the real toilet. She still needed to wear diapers at night.

All three of my boys I swore that they'd be in college before they were out of diapers, they were all older than three before they were diaper free, and all ran into stages where they'd be too busy playing and had accidents in their pants.