For some strange reason
many people making money out of escorts put it about that everywhere else is the same or worse.
Why she's putting you off, I don't know, unless she's had lots of people join and leave within days recently. As the drop-out rate for people new to the work at any agency / parlour is usually fairly high, she should be used to this.
I would be amazed if there were not a better agency in Sheffield interested in having you. They'll still be primarily interested in the money though.