I toilet-trained my 2 girls at different age. The first one is 2 1/2 yrs (she's a March baby) and the second one 2 yrs 3 mths (she's a June baby). Both because they had to start school in September. The first one "graduated" with flying colors in 5 days!!!!! The second one took me 2 weeks!
In my opinion, age plays a role here.
The older they are, the more they are aware of their body function (wee & poo), the easier it is. I think 2 1/2 years old is the right age!
A little tip from me, hope you find it useful:
Take them to the toilet or ask them if they want to go to the toilet, first thing in the morning and every 2-3 hours. Basically it'll be morning, before/after lunch, diaper (for nap time), after nap, and before/after dinner. It won't happen right the instant they sit on the toilet, you may have to wait a few minutes.
And look for the clue. When you see they start squeezing their legs or putting the hand between the legs, you know what it means. I didn't even ask, I just took them straight to the toilet.
Don't rush them, wait patiently, give them your brightest smile, clap your hands and say "yeahhh..... you did it" when they actually do it! I find it the best reward they need from us.
