Feel free to use this, but give credit to me if you do! The collision function checks if the mouse is in four circles in the corners, a large rectangle that covers most of the button, and two smaller rectangles at the edges. Add some rectangle rendering code to the AABB function to see the rectangles.
Thanks to @codeGIO for the inspiration, and outline color! Thanks to @toblerone108 for reminding me that I only need two rectangles, instead of three.