The other way to sex them is to look for hemipenal bulges,
at the base of the tail males have them and females do not.
Males look like a v where females are flat no hemipenal bulges.
Like you said they may not be old enough to tell. I will try to add photos to my web site this weekend showing male Saharan hemipenal bulges and females lack of hemipenal bulges.

Troy
http://www.uroranch.com/
Link