17 months! Don't worry about it, she's still a baby.
From what I've heard most kids are between two and three, often later before they are trained.
My ds is trained at home but still wears a nappy when we go out, he's 2 and 7 months.
I actually don't know any children personally who have tt before two, they just don't have the bladder conrol.
I know it's hard, but ignore you're mum. You are her mum and you will know when she's ready.
Hth xx