How can you tell the difference between a male and a female bearded dragon And how long had a male bearded dragon grown or a female?

You can tell by turning them over and checking between their rear legs. This is however very difficult unless you know what you are looking for. Just above the "vent" there will be either two bumps on the tail, if so, it is a male. Or, if there is only one bump just above the vent, then you have a female. Be careful with your bearded dragon. Just gently lift the tail and look. You will not be able to sex them until they are about 6 months old or take it to the vet .

A bearded dragon can usually reach their full size within about a year or so. Sometimes this can take longer but in most cases they will be full size after a year. It also depends on the size of their tank. They will grow faster in a larger tank than a smaller one. I had one dragon that wasn't growing as fast as the others, I separated her for about 2 months putting her in a 40 gallon by herself until she was about the same size and was able to be returned with the others. Most books will say about 20 gallons per dragon. I feel that the smallest tank for an adult should be at least a 40 gallon (breeder) tank.

Added: Please don't turn the dragon upside down on his back. They cannot breathe well. You can look at the underside of the thighs. An adult male will have femoral pores which look like bumps that may have a waxy look in the center. A female will have them but they are very small, pinpoint-like. You can also hold it in the palm of you hand, place your thumb on top and gently lift the tail upwards. Look at the base of the underside of the tail. Just below the vent (poop hole) on the tail side you will see either central mound (female) or 2 oblong bumps (male). If the dragon is an adult you should be able to tell pretty easily. I wouldn't recommend a sexing probe for someone who doesnt know how to use one. An adult dragon needs 48"x18"-24" enclosure to be comfortable.