Because she is younger, she will have more accidents as it will take longer for her to associate the feeling with needing to go. I would save yourself some heartache though and put her in waterproof training pants instead of underpants so the messes aren't as hard to clean up and if you get good ones, then you won't have as much laundry.
The couple books I would recommend is Jill Lekovic's Diaper Free Before 3 as well as Azrin and Foxx's Toilet Train in a Day. It probably won't be a day since she is so young, but the strategies they say will work for a 20 month old.
It's great that she is shtarting the lead, but you will need a lot more patience with the younger age.
On the go, you definitely want to have plastic pants to contain any accidents as well as cloth wipes to pick them up. Grocery bags to hold the wet accidents. I also used to have 1 change of clothes per hour we were gone, as well as a toilet topper or something that she is willing to go in while you are out and about.
It's hard not to push, but as long as she is showing signs, I would go with it, but you need to make it as easy on yourself as possible as to not be frustrated with the accidents.
Good Luck!!!
Btw- for what it's worth, in other countries, they think we are crazy for waiting so long. Most Asian babies are trained by 1 year, and African babies even younger. There is a big benefit to starting younger before they get into the "no" stage.