Underweight bearded dragon?

I'm new to the bearded dragon but have always had a love form them. I got a bearded dragon about a month ago from petco. I have no idea how old it is but I measured it today and it is 7 inches long from tip of tail to snout. I also weighted it using one of my science three beam balances, it is my classroom pet. It weights 10.5 grams. Now another thing is I have another bearded dragon in the tank with it Hand the other one you can tell it has grown since we have had it. Now I know people say to only get one, but I have also seen that people have gotten two and they were fine. So I am playing a gambling game with them. If worse case scenario is, that my bearded dragons can't live together I have a spare tank to put it in but I don't want to have to do this unless I absolutely have to, because it is currently being used for a different animal, but if need be we can fix their old cage so I can have the tank. Since I'm a teacher I wouldn't be able to feed it three times a day like I do here at school. I do feed them three times a day of crickets. I have a cricket keeper that i bring from home and shake out whatever crickets have climbed into the tube. I also feed them a few meal worms a day, a small pinch of kelp, a small pinch of broccoli, and 3 small pieces of cut up peaches. They live in a 50 gallon tank as well. I would appreciate it if people would just help me on figuring out if my bearded dragon is underweight or if he is okay, and this only. Today when I dropped a meal worm in front of it, it ate it, but after that it didn't care too much for anymore that I lay out.

Hello,

Unfortunately, you will need to house them separately.
Most of the time, they just don't do well together. It is too much of a risk that something
will happen. If you weren't there & they got in a fight, you might come back to one being
dead or severely injured.
Do you know if they are both male, both female or a male & female?
Many times when keeping more than one in a tank, the other one will get dominated &
wont get enough food or basking area & usually will become ill. If they are stressed, they
wont eat.
We would need to see pictures to determine if he is underweight, or not.

Tracie