Hi Mike,
Check at kingsnake.com/uromastyxhomepage for more breeding info. I'm a longtime uro enthusiast and although I've never bred I've heard some breed as early as 18mo if I remember correctly, but they usually take about 4yrs to mature. Micro's might vary from other species. Above is DeerFarms and LindsayPike's pages. They're both experienced breeders.

Hope that helps!