Preschool a motivator?

I went walking with my friend today. She is also pregnant, but still comfortably in her 2nd trimester. Her son is in my daughter's kindergarten class and her 2nd son will be in the same grade as my 2 year old although he is at least 7 months her senior. Our 3rd's will not be in the same class even though they will be closer in age than our 2nd's. We found that interesting.
She is hoping for a girl. We're happy to be having a boy after 2 girls. So in that I am gleaning all that I can about boys from her. Her oldest son is the model boy child and I hope mine will follow suit - please?
Today she informed me that she has signed up her son for preschool next year. It's a 2 day a week break and the price wasn't too bad. I confided that I would love to put my daughter in something like that and she said she was old enough as long as she is potty trained. (Always a catch!)
We actually have been working on that recently, but I certainly cannot hope that she will be fully equipped by September. Her sister was a few months past 3 before she was fully trained for me. She also had the grand help of an expert potty trainer, her babysitter. I'm in this on my own for the first time and it's kind of intimidating really. And she is bound to regress once the addition to the family arrives in late June, right? I had thoughts to not even try until after the baby comes, but she showed signs of being so ready to start that I felt compelled to give it a try. So we've been at it aggressively on and off for about a week.
Today, she was presenting some resistance to her training. At dinner I mentioned to her that if she could potty train she might be able to go to school next year. She screamed in delight and begged down from her high chair.
As soon as she was released, she ran away. Moments later her sister came back to inform me that she had FILLED the potty. I didn't believe it. She tends to take at least 5-10 minutes before weilding trickling results and I was sure it had been less than a minute, not to mention she had on a diaper not easily removed. I had to see this for myself.
There is was - a half full potty. We dumped it out into the big potty and she delightfully flushed. Then she wanted to go again. She sat down and was reluctant to get up. After a little while I informed her that perhaps it was too early to try again at the moment.
I've not seen a child so excited about learning her ABC's and 123's at 24 months old. Where does she come from? Who knows? Maybe she will be ready?