My parents won't let me join a ballroom dancing class; how do I persuade them

[Susan]

to let me do it? My mom is a very strict lady, and she wants me to do well in academic subjects. I know dancing will not interfere with my studies as I have had a busy schedule all my life, and still have managed to be a straight A student.
It was the programmes like Dancing With The Stars and Strictly Come Dancing that inspired me to try ballroom. And so I did, in my GCSE PE class, when we had 6 weeks to come up with a routine of our choice and perform it. Me and my partner enjoyed doing this task enormously, and started doing even better in and around school. Even our friends noticed how much we changed for the better.
In the end, we got one of the two highest scores in the class, and our teacher advised us to consider doing ballroom and latin american dancing outside of the school.
The class is not that expensive, only £5 ($8) per session, or £24 ($40) per 6 weeks.
How do I persuade my mom to let me take this class?

[Emilio]

Tell her to go jump in a lake but first have her give you $40 bucks for 6 weeks of lessons.

[dreamer]

Just tell her everything you just typed. It would persuade me and i'm stubborn. Lucky the ballet lessons I want to take are expensive

[QuiteNewHere]

tell her that you will do some housework during the weekend or when you are free as payment. or borrow it from her and pay it with babysitting money.

Find babysitting jobs or dog walking around the neighborhood.

[Kelly]

Just say hey can i talk to you about something? and then you say and if you dont want me to its totally fine i understand (and if you dont understand act like you do i got whatever i wanted if i said that lol)