I have no idea, but a "smarter" email would be "mum can I borrow $100, pay you back ASAP, just a bit short today sorry and thanks!"... Mum would be less incline

I have no idea, but a "smarter" email would be "mum can I borrow $100, pay you back ASAP, just a bit short today sorry and thanks!"... Mum would be less inclined to phone you in a panic.