We're going to be talking about problems like withholding in a couple of weeks, so check back then. Just asking her if she is ready is a form of pressure. I would urge you to let her decide on her own. If you want to do anything, put the potty out in the yard with her or in her room, and put her in a dress so she can decide when she wants to go by herself. Be sure she has diapers for naps and at night, so pressure is off part of the day.
Underwear is pressure.
Children know that you are not supposed to wet underwear and that underpants are different from diapers. I wouldn't put her in underwear until she's fully trained. No go there. Drop it for now. When she is ready, she'll let you know.