The book Toilet Training in Less Than a Day worked like a charm on my 27-month-old son (after about 6 months of me trying before finding the book). Don't let anyone tell you she's "not ready" yet. Those are the same folks with four-year-olds in diapers still - that is gross, and an insult to the kid's intelligence. The book should work just as well on a girl. You can find it on amazon. Some people are put off by it because part of the training is teaching the kid that going in their pants is gross and unacceptable. Again, those are the people whose "genius" children are so trained to go in their pants, that it really is a chore to re-train them to go in the toilet so they can start kindergarten.
There are little toilet inserts that you can buy (one is collapsible that can fold up and go in a bag in your purse) to put on a public toilet, so her bottom would only be on that. They feel a little unstable (the collapsible kind) so my kids were afraid they'd fall in. There's the padded kind meant for home use (with elmo on it) that could also be put in a bag in your large purse, and wouldn't feel so shaky.
60 years ago, virtually all kids were potty trained by age two, or soon there after. Parents expected it of their kids, and just did it. That book tells you how to know she's ready, which is simple. You do have to follow all the steps for it to work. They tested the method in a research setting, and had 100% success as long as both parents were on board (hard to imagine that a parent wouldn't be all for it, but those are the same sorts referenced above). In preparation for training her with that method, you could be teaching her the difference between wet and dry, and teach her how to pull her pants up and down, and stock up on panties that she helps you pick out (loose fitting, that she can get up and down), and since she is so small, a little potty seat that she can empty herself. If you are short on time for reading the book, you can skip the first three chapters (they talk about the research methods and such). The training starts with chapter 4. The method teaches them to go to the bathroom independently, without your help. People were amazed when we'd go to their home, and my little tiny guy would get up and go to the bathroom by himself, without asking for help or anything, and finish with washing his hands and everything (if they had a stool in there). It's well worth the effort of one day. Good luck!