If you are into men, and you have small penis, you must look into either non-penile inversion (Suporn and Chettawut and few other Thai surgens) or colon vaginoplasty. With colon option, most surgeons do vaginoplasty with sigmoid colon segment, which is an overall a terrible choice and unnecessary, as ileum and jejunal small intestine graftsare a lot more appropriate and surgery is less invasive, less short and long term problems than with sigmoid colon, and you dont have to even have a abdominal scar like with sigmoid colon...
If you are into men,... 12 cm is literally nothing. Especially if that 12cm is measured in a position that you dilate in (legs straight), that means you actually have 10cm or 9cm in actual sex positions with bent legs... thats literally nothing...