A dragon is considered a juvenile when it's body is approx. 3 inches in length from the snout to the vent, and if the tail is intact, when the dragons total length is approx. 10 to 12 inches. When they reach this size they are usually about a year old, and yes they still look female.
You'll notice that below the spikes there is a ridge of bone or cartilage under the skin that points upward, just as the spikes do. I don't know if there is a proper term for this characteristic but I call them vertebral spikes. On an adult male these bony protrusions under the skin, below the spikes are approximately 1/2 inch long (1.2 cm).
The femoral pores will feel bumpy compared to a females which will continue to stay small, smooth and indistinct.
As the male dragon approaches adulthood you should notice that his body is also more triangular shaped ... upward triangular, and that the base of the tail is much more triangular than that of a female.
An adult females body is more rounded or pear shaped (especially in the abdominal area), and her tail should remain rounded in appearance.