Maybe you can slowly tell her like make random casual comments about emo benefits like additional distressing and making you more productive with you days. Give her some good example then she'll be more open minded.
You are genius! I'm definitely going for doing it!! 
Just tell them OP. Have a long discussion about it basically lol but parents will be parents and good luck!
You are welcome 
Do you want to dress like an emo or what?
Of course, because I'm emo like I said before LMAO Can't you read? Remember you are interacting with emotional being.