laying eggs isn't the only reason dragons dig. Some dig out of boredom, some dig to find a cooler place to rest. Some dig because they want to brumate and a dark burrow is where they would normally do it in the wild. Some may dig if they just saw a tasty bug disappear into the ground.
If your dragon was a female and developed infertile eggs (it is possible to happen at 10 months but it's not the normal, most won't till at least a year old, are mated, or are cooled in their first year for some reason), you should be able to feel the eggs in her stomach with gentle massasaging. She will also stop eating completely within a few days of egg laying. Digging can happen as early as a week before she is ready to lay eggs.
I am personally leary about breeders who claim their dragons are a certain sex when the dragon is less than 12" long or 6 months old. Most sexual characteristics are not even developed at that age, so there is a good margin of error. A really experienced breeder who had been sexing dragons young for a long time, may have a better change to get the sex right but there is always a margin for error.
The best way to sex a dragon is to wait till it is 6 months old or more, place the dragon on a flat surface (the palm of your hand if he is calm or a table top you can bend down to see at eye level). Make sure the dragon is facing away from you. Lift the tail up about 90 degrees, and while twisting it gently, look at the base of the tail, on the tail side of the vent, for either two bulges (or a dimple in the middle) which indicates a male, or a single central bump, which indicates a female.
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PHLdyPayne