Remember, the “c” in ec stands for communication, not catching. Some ec parents say that when you stop talking about catches and misses, you start listening and observing. Baby is not put off by someone who listens and observes.
After she squirms and yells, does she go? Or at some other time? Are you having some diaper-free time every day?
Till you pick up her rhythms and signals, the easiest time to offer the potty is right after she wakes up. You can also try right after she pees or poops, in case there is more to come. She may show you her own ec positions. Like all the other talking you do around / with her, you can talk about hygiene without expecting a specific response or knowing how much she understands. Or you can wait a few months while still letting her communicate, unimpeded by the diaper.
Chat up others having the ec fun at: Elimination Communication.