There are far too many variables involved for anybody to be able to give you an accurate age.
Also, the shed skin is not an accurate form of measuring snakes. The sheds are actually longer than the snake. I've heard anywhere from 10-15% longer. But I'm not really sure.
Also, you definitely can't tell male or female by size, especially as juveniles.
Lastly, many of us use the free app Tapatalk to upload pics directly to the forum.