I made less then $4,000.00 last year babysitting but got paid under the table now she wants to claim it on her taxes but would I have to pay taxes on it?

Last year I babysat for a lady and made less then $4,000.00 but now she wants to claim it on her taxes as a childcare write off but I want to know if I would have to pay taxes or a self employment taxe? Thanks any information will help as she did not tell me this when I first started.