First of all, I would tell you that this is more common than you think and there is no specific age limit to have a breast augmentation! Many women do not undergo a breast augmentation until their last child goes to college. The breasts can deflate and lose the youthful appearance they once had after children and as we age.
The majority of women in this range want an implant that is just going to restore what they have lost an restore their breasts to a more youthful appearing shape. Something that will look good in a nice dress, business clothes or a bikini!
If you are in good health there is no reason that you could not have a breast augmentation even at a more mature age.
I encourage you to see a board certified plastic surgeon to discuss your options!