Guys, which would you prefer?

Hi, I'm a 21 year old girl and am considering getting a breast augmentation. I know that men would usually prefer a woman to be natural, but I am natural pretty flat-chested, as I am thin and don't have that much body fat. I don't want to gain weight as I am healthy and get compliments on my body from guys (excluding my boobs,) but I am getting older and really don't feel like a woman with the size I have now. If I were to get them I would get something very natural, like a full B/small C, as something bigger would look ridiculous on my small frame. Knowing that men would always prefer natural (large) breasts, which would you guys prefer: natural (VERY) small breasts, or fake boobs? I don't want a guy to see me as shallow just because of my boobs but I don't want to be flat either. I guess I just need your help choosing the least of evils. Guys, what do you think? Thanks for your help :)