...and her view was "in a few years you wont have a choice but now you do, and I prefer it as it is now".
Look at it this way. She has a point...you do have a choice now, considering how short it already is. So using her logic, your "choice" would be to grow it back for three or five days after going slick sly. Not a huge risk and you'll likely enjoy the results, and maybe she will too.
Another idea: ask her to help you with the head shave!