But now that the cat's out of the bag, you need to know some things. But there's been much debate over this issue. The accepted average in one area of the world may be different than another region. There's been no worldwide study of penis lengths. There's also the issue of girth.
Many women appreciate a wide cock compared to a too long one that pokes around painfully.
So you could be short in terms of length but just right in terms of width. Also, your girlfriend's vagina may just be too big for you. She might be a tall girl, and you could be better suited to a short girl. Believe me, the height of your partner makes a big difference. In conclusion, be happy with yourself.