Typically females are not that deep. But one of my holdback diamond babies probed 8 scales deep and it was the runt in the litter. He turned out to be a she. So yours could be a female as well. If the snake is 3 years old a females shed could possibly tell you if its a male.
Also some males will invert during a bowel movement.
Ed M.
www.EmeraldTreeBoa.com