This is a great question as many women have their breast augmentation at a young age. The short answer is that breast implants do not keep you from being able to breast feed.
It is important to keep in mind that not every woman can breast feed even if they have never had any type of breast surgery or breast augmentation. If women have problems with breast feeding after an augmentation it is typically due to nipple sensitivity. This occurs in less than 15% of women.
This is an important discussion to have with your board-certified plastic surgeon prior to your breast augmentation.