Lack of penis size during erection, the possibility of successful fertilization

Hello doctor. I am 32 years old . I was born at 7 months during her pregnancy my mother(premature) because I had a sister a twin sister. Was because my sister since I was little died.
Well, in short, I am not satisfied with my size of my private parts(members). When it's cost is only 13-15 cm, the thickness may be the norm, but that's just the length of me, still eating. And when not, at all, as if it is not present. Did what I was born premature, and is it possible to fix this without causing harm to my health now in the age of 32. I fear for my health because I have no children. If so, how? Thanks in advance.

Response: "Hello! You have nothing to worry over their health. The size of the penis you have is normal and something You're born premature is not related to your reproductive health. To assess the chance of paternity is necessary to investigate spermogrammu with MAR-test. I wish you health"