Tell her you respect everything but you cant get beyond the fact that your eyebrows are embarrassing for you and thats all you ask of. If I were you I would just purchase some tweezers, look up a tutorial online and do it myself. Just get rid of the ones that are scattered and dont go with the natural flow of your brown and repeat on the other side. Times are changed and people are not as understanding as before when your mom was eighteen. I dont think you will convince your mom, you need to take matters into your own hands (if you really want to) what can they do to your for plucking your eyebrows? lol they CANNOT kill you.