Wrt potty training, I thought my son would never do it. He trained at about 3.5 yrs old, in two weeks. Really, it was less than that, but that's as long as it took for me to feel comfortable that he wouldn't have accidents. His issue, if you will, was that he is a huge perfectionist. He will not attempt most things unless he's sure that he can do it. And he doesn't like to make a mess. So he wouldn't even attempt toileting, because it was too much of a "what if" for him. When he was finally ready, he did it all the way. It took minimal coaching on our part. I'm biased from my one measley experience, but anything less than 3yrs old seems really early to me.
I have a question, totally unrelated. Do any of your extended family act weird about your dc's giftedness?
My ILs are wonderful people. I adore them so much. They are wonderful with my children. My MIL is in early education and not only is she a natural with children, but she's a huge supporter of our decision to homeschool. But she's a bit weird about ds1's abilities. They get regular emails from me, updating them on the kids. Dh talks to them every week too (we live a long way from them).
Ds has been writing/copying words for almost a year. I've mailed them things that he's made, including a recent note that I dictated to him. But on a recent visit, MIL said, in an astonished voice to me, "Wait until you see this. Ds wrote the letter, 'B'!"

Later, they were drawing and ds wanted to draw seaweed. They were going to "help" him, but he talked over them, saying, "First, we need to draw a rectangle for the bottom." Then, he apparently traced his hand above that to make the seaweed effect. I was reading in the other room and I heard MIL ask him, in a hushed tone, "Did your mother show you how to do that?" I heard him reply, "No." and then she asked, "Did your Daddy show you that?"
In the past, when he was comfortably doing 60 piece puzzles, she would "help" him do, like, 24 piece puzzles that he mastered at 24 months. I didn't care, as long as he was having fun, but then, she'd make a big deal to me how he got some sky piece in by himself.

Also, at our recent visit, she exclaimed, "You know how to use scissors!!", when I had recently sent a photo of a detailed paper digger that ds created by himself; among the many cut pieces were tiny cut triangles for the shovel of the digger.
She's a great MIL and a wonderful grandmother. The way I look at it, she's excited about spending time with the kids and ds1 is having fun. He has the kind of personality that "hides" a lot of who he is. If you met him, you might not hear much out of him. Plus, he jumps at the chance to do anything with his grandparents. He'd gladly do a 4 piece puzzle if it meant spending time with them. He's very unaware of levels right now; he just does what makes him happy.
So, I realize this is probably a non-issue since they're all having fun. But it drives me nuts on some level, because now I'm paranoid that they think I'm exaggerating his abilities. I guess I don't want them to think that I'm a braggy mother who is making things up or embellishing things for attention. I'm not! I am very matter-of-fact about things. If he were learning the alphabet for the first time, I'd have the same approach and tone.
Anyway, I guess that's more of a vent than anything else. I'm curious if anyone else's family is skeptical or weird about this sort of thing.