For some reason there is a massive myth out there that the main way to lose fat is by exercising.
But the real way is food. The equation for fat loss is 30% exercise and 70% what you eat.
I highly recommend following the Bodytrim lifestyle designed by Geoff Jowett as it brings results.
Eat...
Weightlifting will have the opposite effect if anything. As long as you don't lift to heavy till you have finished growing. Weightlifting can only benefit you.