Ask to buy can be turned off by the Family Organizer without needing you to leave Family sharing.
click here ➜ Approve what kids buy with Ask to Buy - Apple Support
But to answer your questions:
if I left the family sharing would ask to buy turn off also
Yes, as without the Family Sharing group, there would be no one to approve the purchase request
if I left the family sharing would any music I got/downloaded through the music app stay on my phone?
Depends.
If the music was purchased from the iTunes Store, it should remain.
Music obtained through the Apple Music subscription service will be removed, unless you activate your own Apple Music subscription before leaving the Family Sharing group.
Raynedome wrote:
Today is my 18th birthday and while now that I can leave family sharing and other stuff I still have to ask for permission to get apps which is kind crap. And I was woundering if I left the family sharing would ask to buy turn off also if I left the family sharing would any music I got/downloaded through the music app stay on my phone?