LOVE small breasts
My current wife is a small B, sometimes A depending on the particular garment. As was my first wife. I have always found small breasts infinitely more attractive than large ones, and would never even date a woman who has had implants.
Small breasts are, in my experienced, much more senstitive than large ones. Large breasted women invariably get less enjoyment from breast play.
If you are blessed with small breasts, please, please please do not change them. Revel in the perfection of them. They won't sag or become distended, they will function perfectly, and they will excite the right man no end.