Payment and Shipping Edit Button Greyed Out

So the other day I wanted to buy something on my phone and I went to the game and clicked the button to buy the item. However it said that I had to verify the card. When I went to verify it, it was the wrong card. So I went to my Apple ID and went to Payments and Shipping. There’s a button on the top right that says edit, but it’s greyed out and I believe it’s due to my phone having family sharing on. So I went to my family sharing and I saw that my Mom was the one I am sharing with, but it’s her old phone. I need help to either turn off family sharing or be able to change my card info some other way. I am on an IPhone 8. Thank you.