Take this for what it is worth coming from a geezer with a teenager...
Especially for first time parents who have a child who clearly smart, it can be very easy to overestimate their overall developmental maturity during the toddler and preschooler years. That can lead to a lot of frustration on both sides. It can lead to parents expecting too much and ascribing negative intent to the child when they can't/don't comply and days can be spent engaged in frustrating power struggles that really don't need to exist.
17 months is very early to try to get a kid using the potty. If she's saying she wants to go potty and then isn't doing so it could be a lot of things. Yes, you could call that lying, but instead it may be that she's 17 months old and planning activities and carrying them out consistently is not a developmentally appropriate expectation. It could be that she wants the positive interaction with adults she gets when she says she needs to use the potty. It could be that she intends to potty but when she sees other alternatives in the bathroom she forgets about that or moves on. It could be that really when she says potty she's not totally getting what that means to you - you have a conception that it means get to the task but she thinks it means play in the sink. She doesn't get the long term goal of what it means to be potty trained so she doesn't get why the focus needs to be carried out in this particular way.
So, from the geezer section of the bleachers... she's really still a baby. Try to assume positive intention behind what she says. She sees the world differently than you do and she's learning in a way that is appropriate for her. Focus more on celebrating this time because it really does go too fast.
