Creating a B cup through chest surgery

I'm really worried about having a very small chest, so I'm considering breast surgery~ I want to have implants, but I'm worried that a too large implant might look awkward!

I'm thinking of trying to put in a slightly smaller implant without being greedy! But usually, a B cup is average, so isn't it natural?

I'm considering making it about a B cup, but I'm worried it might be too small. How natural does the size look after implant surgery?