ball size

[cdballs]

Iguess the average ball size is 5x2x3 length width height in cm mine are 6.4x3.8x3.8 and they do a a calculation like 6.4x3.8x3.8x.52=48 which is the volume and i guess the average is 18 to 30 are mine huge big or just average jw cause i never thought they were any thing but normal until i read up on this an i thinking a litttle differently now?
also does ball size matter to girls that bust are sertain sizes better for sertain bust? thought you might know thanks