Wanting to be a moderate B cup or Full B Cup, is 250cc too big to achieve this? (photo)

Trying to establish an exact cup size with breast augmentation is almost impossible. The important thing is to communicate effectively the look that you are trying to establish with your surgeon. After that, you will just need to trust him/her to deliver the results that you are anticipating. 250 cc implants are conservative and will certainly give you a natural appearance. But I would guess that they would make you a C cup. The difference between a 250cc implant and a 225cc implant is not that much. You could probably do either one and be very happy. Be prepared to fit a C cup bra though.

Thank you for the question and pictures. Unfortunately, online consultants will not be able to provide you with specific enough advice to be truly helpful.
Generally speaking, the best online advice I can give to ladies who are considering  breast augmentation surgery ( regarding breast implant size/profile selection) is:
1. Concentrate on choosing your plastic surgeon carefully.  Concentrate on appropriate training, certification, and the ability of the plastic surgeon to achieve the results you're looking for. Ask to see lots of examples of his/her work.

2. Have a full discussion and communication regarding your desired goals  with your plastic surgeon. This communication will be critical in determining  breast implant size/type/profile will most likely help achieve your goals. 
In my practice, the use of photographs of “goal” pictures (and breasts that are too big or too small) is very helpful. I have found that the use of words such as  “natural”  or “full B, small C cup”  etc means different things to different people and therefore prove unhelpful.
 Also, as you know, cup size varies depending on him who makes the bra; therefore, discussing desired cup  size may also be inaccurate.
 The use of computer imaging technology may also be very helpful during this communication process.

3.  Once you feel you have communicated your goals clearly,  allow your plastic surgeon to use his/her years of experience/judgment to choose the breast implant size/profile that will best meet your goals.  Again, in my practice, this decision is usually made during surgery.
I hope this (and the attached link) help.

Thank you for your question and photographs.  You have very natural normal looking pretty breasts.  The 250 cc breast implant should give you a full seen small be but if you are concern discuss this with your plastic surgeon.  Going down to a to 25 is only a tablespoon of volume and I don't believe will look much different.