An attempt at potty training a 20 month little girl

Well today is day one of the potty training process. We got her A small potty; since previous encounters with the normal potty were quite terrifying to McCall, and also got some training pants and regular panties, we got some smarties for rewards, and let the fun begin. 

...except wait it hasn't been fun at all! Oh my word this morning has been soooo frustrating. I gave her a small Gatorade to drink and set the timer for 15 min. EVERYTIME that stinking timer went off I put her on the potty...she sat and sat and sat, and every time; just after I would take her off the potty she would pee in her underwear. I would tell her the whole drill of no peeing in big girl panties only in your potty. I feel like I'm talking to a wall. So after a load of peed on underwear and a bath I put her down for a nap. We will make an attempt when she wakes up and hope she is well rested and ready to take on potty training.