If so many people are telling you she's not ready, and if the incentive charts aren't working, maybe the others are right. Can you say more about why you think that is such incorrect advice? Can you say more about why you are "concerned"? Is it because it's inconvenient? Is it because you think others are measuring your child's "advancement" or development by one single milestone, which is potty training?
If you search on Mamapedia, you will find dozens of questions on this subject, and tons of responses to each post. You can see differences in opinion, from people saying that kids are trained at 11 months in Europe, to people saying their kids didn't learn this skill until age 4.
I'm in the latter camp. Moreover, i can tell you that there are a few areas where the kids will do stuff when they are ready. One is using the potty, another is eating new foods, another is sleeping, another is walking, another is talking. My kid walked at 8.5 months, but do you think other parents were "concerned" about kids who didn't walk until 12 months? Conversely, my kid didn't talk until 16 months - probably because he was walking and building and exploring outside and a whole bunch of other things. If you set this up as a power struggle, it will make both you and your daughter miserable. I suggest you put the nice underwear in the drawer, keep a little potty in the bathroom and tell her she can use it when she wants to, and put her back in diapers or pull ups. This is not a behavioral issues for most kids - it's a developmental stage where they actually feel the full bladder, the signal gets to the brain, and the brain says "hold it in until you get to the bathroom and then release the sphincter muscle." My guess is, your kid is doing a ton of things right as she should be - some "early", some "late."
Don't shame her, and don't let anyone else shame you. This actually is not something you can teach a kid if their body isn't ready. Just my 2 cents.