There's almost a cup size difference between my breasts. Dear Reader, This is not something to worry about.
Few women have identical breasts.
The difference between each breast, or even nipple, can be slight, or more obvious, especially after puberty. Breast size and shape are unique for each woman. Throughout a woman's lifetime, breast size and shape change in response to fluctuation in hormone levels. Knowing that your breasts will go through normal changes may make you feel more comfortable. Becoming familiar with your breasts will help you to notice any changes in your breast tissue that may be a cause for concern.