You're not overtraining as long as you sleep 6+ hours a night (necessary for recovery, 8 is recommended).
5 months serious lifting
8 hours/night sleep
7% bodyfat (every ounce in my chest and belly, always amazes me how it's concentrated!)
I'm doing Dr. B's Precision Nutrition (not counting calories for a few weeks till I accomplish the first goals). Was eating around 4200 a week before I stopped counting (now they're significantly lower for a while but I feel great).
I started lifting on my own for the first 2 months, did CW's 10x3 for fat loss, and now am doing his Bodybuilding's New Frontier high frequency program putting in 8 workouts a week. I do contrast showers, dynamic stretching (from the magnificent mobility dvd), and just started using a foam roller. In addition to spending about 12 hours a week doing this, I dance 6 hours a week, and often go hiking on the weekends for a full day to relax. I wasn't very active before lifting weights, so being 17 with much the same stats (though I don't know your height or bodyfat), as long as your diet is fairly clean and you're sleeping, you're fine.
I've overtrained in the distant past... happened because of bad diet and lack of sleep... with adequate sleep and diet (especially with only 1 workout a day), I think it's almost impossible to overtrain.