Potty training

I'm having difficulty potty training. We tried a couple months ago and she pooped on the potty and got a reward. After a couple days of trying she wanted nothing to do with the potty so I put it away. I brought it back out two weeks ago as she tells me when she sometimes has to go to the bathroom but every time I mention potty she screams no. She understands she will get a reward, we have tried songs I have sat with her and held her hand while on the potty. I swear I've tried everything. She holds her pee until I put underwear on her or a diaper. Do you think maybe still too young or she will do it when she's ready Any advice would be greatly appreciated!! Thanks ladies