Well K., you are right each child is different, and that makes a big differnce in potty training. I had six children and helped to potty train many grand children, so I will tell you in my opinion it is never too early to get that task going. Some, learn quickly, some are stubborn, and some can't wait to sit and potty train. I found that the girls learned more quickly for me, as long as they saw me going, and they had a potty chair near by to sit on.
They boys had no problem standing on a little step-stool to pee, but didn't like siting on toilet or potty chair. My big son, potty trained shortly after he walked, with the help of my mom, and 2 brothers, who showed him the ropes. He couldn't wait to pee like a big boy, and sit on the little toilet to do his duty, which he would read his little books from, while he sat their. Then I had a son, who refused to relinquish his fluids in the toilet but had know problem in peeing on a tree or bush out side. He was 1-1/2 at that time, and at 26years is still doing that. That's boys for you. So, I recommend that you start as early after they get the walking thing going, and are stable, and you have a potty chair near by, and a step-stool, plenty of books, and things that make the experience enjoyable. Curiosity about what you are doing in there, usually sparks the interest to do the same.
Children learn from what they see, and experience. They also need encouragement and praise while learning. Rewards work great, when they get it for trying and doing it. Make it a great experience and you'll see the results happen faster. Buy those pull ups, instead of pampers, and start with using them during the day, after they have been bathed and dressed for the day. Remind them that the pullups are like panties, or underware, and that they should not go in them, but that they should not worry if they make a misstake, cause they can put new pullups on. After you master that for a while, try buying them cute little underware, that they don't want to get dirty. Show them how to wash them out if they mess up. That's always been effective to my children and grands. It helps them take resposibility for themselfs and what they do, and then they don't feel ashamed.
Make it a game, that wins every time, even if they mess up. Find a way to reward them for trying. If you have any more questions, I will be glad to answer the best I can.
Good Luck, and remember the earlier the better, because they won't have a chance to argue about it.