My youngest (but not for long) is just over 3 years old. He is very smart (I know many parents say that about their own kids, but it’s true). But he can be a stubborn ass.
There has been a few times now we attempted potty training with him. With our first son, we had a few struggles, but he got it down pretty quick. Francis (our youngest) on the other hand, seems to be testing how far my patience will go.