I highly doubt someone who grew their hair so long would be happy if you chopped it without her knowing and I highly doubt she would say yes because you don't put up with hair that long for no reason. I don't know the circumstances that lead you to co-sleep with your Mother, no judgement, but the best solution I see to your issue would be, if at all possible, to quit co-sleeping with your Mother. If she questions why you quit co-sleeping with her I would say that her long hair was bothering you in some way, I doubt that will lead to a haircut but maybe you can redirect you attraction in a more healthy direction.