Have you heard the saying 'I'll stand on my head and cut corks', This was often the reply I would get from my Mother , after asking her what She is going to do, specifically when She had to solve a problem.
I suspect you would need to ask your mother, it may be a family thing. The sentence appears completely nonsensical and I would say that it means she hasn't a clue, that she needed time to think.
Thank you for your answer "froggequene", unfortunatly my Mother passed away years ago, and just like this question I have hundreds more that I wished I had asked Her before She Died. Thank you very much though, yes perhaps it was another way of saying "I have'nt a clue". Gaffer.