My DD wouldn't potty learn until 3.5, so a little younger but still much older than everyone else we knew. I think a lot depends on the kid and the dynamic you have going on with it. We don't do rewards and punishments so that wasn't something we tried but I know that does work for many families. Mentioning who was potty-learned didn't motivate DD at all, but that can work for some bc they want to be like their friends or older kids.
I think at this age it is very difficult bc they are so willful and if you are making a big deal about it she may continue to fight you. There is NO WAY I would be cleaning underwear all day for a kid who refused to use the toilet. I'd put her back in diapers (pullups I think are useless) until she will do it. With DD I told her we were not buying more after the current diapers were gone and she freaked out, said No Way! but I replied, Oh and let it go and a week later she told me we were not buying any more diapers and that was it. She put on underwear, had one accident when she was too busy to go potty and that was it.
So I guess at this age I would explain that she is old enough to use the potty and be out of diapers, but if she didn't want to she'd be using diapers and just lay off it. Take her shopping for underwear she likes. That motivated DD. She wanted to wear them, and I explained that she could wear them if she would use the potty all day. And if there were an accident, oh well, no upset on your part, but have her help you clean herself up. Take all the pressure off, don't guilt, shame, get frustrated, etc. Are the kids in day care her age? I'd think peer pressure would come into play eventually if she is the only one in diapers at her age. I would think daycare would rather have 4 yos using the potty than changing diapers, so I am surprised they won't do what you want them to in this regard. Sorry, I cant be more helpful. I know it is very frustrating having a kid that won't potty learn but ultimately it is up to her and the more you try to force the issue the more she will dig in her heels.