Well first of all, i couldnt tell you the age although id say around 2-3 months from the size, which also means u wont be able to tell the sex of it untill 5-6 months(unless your really experienced) so its basically just the waiting game. When it comes to the tail, dont even worry about that too much as of yet, they use most of the food to grow when they are young, they usually start storing the fat when they dont need it as much, But its tail does look rather skinny even for a youngster, try feeding him everyday, atleast offer it to him, if he doesnt take it everyday then its fine, but offering it ckrickets/hoppers etc may encourage it.
As for its morph, try this youtube vid:
http://www.youtube.com/watch?v=XEOieGVc8JU
hope this all helps dude. X P.S. DO NOT FEED IT WAX WORMS, it will get addicted and you wont be able to get it back on crickets for ages. so it seriously IS best to keep it of them, they dont call it gecko crack for nothing. lol. :P