I Feel Insecure Because of my Small Breasts. Age 18, 32A; What Can I Do?

Congratulations on taking the time to do research; this is a great first
step. Please also read Dr. Peter Johnson's answer--each of us should consider
those steps for women who express concerns such as yours BEFORE offering breast
implants.But for the mature, well-adjusted, informed young woman who wants breast
implants, this is still the best way to obtain larger breasts. (The
rest--attitude, self-esteem, confidence--is up to you!)But I do want to clear up one misconception that many of my colleagues
erroneously promote in their responses (here and in other answers). At
age 18 you can certainly have silicone gel breast implants! They are
perfectly legal for use in the well-informed woman who requests their use. Use
of silicone gel implants in a woman age 18-22 would be considered
"off-label" use, just as Botox use for forehead frown lines is
perfectly legal, done all the time, but still considered off-label use, since
the FDA has not approved Botox for the treatment of forehead lines (yet). But
Botox is a safe and FDA-approved pharmaceutical that can be utilized by
individual physicians in any way felt appropriate for their informed and
consenting patients. The same is true for use of silicone gel implants in a
woman under age 22!Please continue your research and see one or more ABPS-certified plastic
surgeons. Be careful about "cosmetic surgeons" who may have little or
no training in plastic surgery and receive their "board
certification" from bogus boards or Board other than the American Board of
Plastic Surgery. Click on the web reference link below for more information.
Best wishes! Dr. Tholen

You may be a candidate for breast augmentation.    In order to make an accurate size recommendation, I would need to assess your chest wall and breast mound measurements and characteristics.  Unfortunately, there is not a general rule of thumb or objective criteria to implant selection.

Your plastic surgeon will perform several measurements of your chest wall and breast anatomy and determine a range of implants that both fit your chest wall and reach your desired goals.
The next step is to try on this range of implants in the office with your doctor.   The key to this success is showing your surgeon the body proportion you desire with a bra sizer and allowing your surgeon to guide you to the right implant.   It will be much easier to communicate in implant cc's than cup size when determining the appropriate implant for you.
I wish you a safe recovery and fantastic result.
Dr. Gill

We all experience insecurities about ourselves.  Breast enhancement may address that area of concern for you.  I would recommend a visit to a Board Certified plastic surgeon to learn more about implants.  There are risks and benefits associated with them and learning about them may help you decide if they are right for you.  

I would also encourage you to visit with your gynecologist to explore the reason for your irregular menstrual cycles.

Best wishes