How long til you can determine final size after lift/mild reduction. (photo)

I appreciate your question.
You are still very early and cup size is not guaranteed. In fact, the more tissue you remove, the higher chance of having complications such as nipple necrosis and.or los of sensation.
I perform a liposuction breast lift that removes tissue from the areas you don't want such as near the armpit and the lower portion hanging near your stomach. Once I use this to shape the breast I then remove the skin to tighten the breast and create a better shape with nice cleavage. Since I perform this less invasively the recovery time is faster and drains are not necessary. The size would depend on the proportion with your body versus going for a cup size. It works very well if there are asymmetries. I can also use the removed fat as a natural breast augmentation by grafting the fat back into the breast to create more projection or into the top to create more cleavage. If you have shoulder grooves from your bras, I can also use the fat to fill these areas in and give you more cushioning as well as contour. This procedure can also be combined with an implant if needed or wanted.  It should not affect nipple sensation, mammograms, cancer risk or breast-feeding. If you gain or lose weight, the transferred fat can do the same.
The best way to assess and give true advice would be an in-person exam.  Please see a board-certified plastic surgeon that specializes in aesthetic plastic surgery.  
Best of luck!    
Dr. Schwartz 
Board Certified Plastic Surgeon
#RealSelf100Surgeon 
#RealSelfCORESurgeon

Thank you for your question. It usually takes about 3 months for all the swelling to go down. I would continue to wear a sports bra to provide support until you are comfortable wearing an underwire bra.

It usually takes at least three months after surgery for enough of the swelling to go down to determine the final size. 

The truth is, the cup size is not an accurate measurement as it may differ among manufacturers.  But to allay your concern, expect some changes up to six months.  First and foremost, the postop swelling may somewhat hide the results.  Furthermore, the skin will relax a bit as you move forward to your recovery; hence, some of the upper pole fullness may dissipate, while the lower pole might appear rounder. 

Good luck and best wishes.