My oldest had clear interest before 18mo (so we put out a potty and talked about it) and she was ready at 19mo (she pulled off her diaper by herself and peed in the potty), so I don't think it's too young-all depends on the child. And at the early stage of becoming aware of her body, it's hard for her to tell you before it happens, but she's connected where it was supposed to go-which explains her insistent screaming.

I would clean her up then put her on if she's asking. I wouldn't work further on offering or training if she's only there a few more weeks. Only if she asks, and if her bottom is clean.