Resistance to Toilet Training
Lots of things can cause a child to resist the potty from the get-go or suddenly start to refuse the potty.
If your toddler freaked out the very first time you put them on the potty and hasn't gone near it since, don't worry. It's pretty normal. For a kid who's spent most of their life with their bottom covering in warm, soft material the cold, hard potty chair and open air can be a bit of a shock. Not to mention no toddler wants to be taken from their play things to sit still on a hard plastic chair. They don't really understand what you want them to do anyway so it really just feels like a time-out.
If your toddler has been doing okay with the potty but suddenly hates it there are a few causes. A) some sort of traumatic experience like falling off the potty, smashing their fingers (or other appendages) in the potty, a loud noise while using, etc. can make them wary of pottying. B) The novelty wore off. It was fun at first because they got all sorts of attention from mom & dad, but now it's boring. They just want to play. C) Some big change is going on in their life and they can't handle that stress plus trying to wrap their minds around potty training. Even hitting new cognitive milestones can make a child suddenly want to stop the whole potty training thing.
No matter when you decide to potty train it has to be done gently. Let them play with the potty and sit on it fully clothed. Read them stories while they sit or play games. Let them sit as long as they will tolerate it but let them off as soon as they start to fuss. If they don't go then try again in 10-15min. If they're having a bad day/week/month with the potty it's okay to take a little break. Just know that you may be back to square one when you go back to it. They should get back to where you left off relatively quickly though.
We got really lucky with potty training Mason and Audrey - crossing my fingers Hayden is just as easy!