My elder daughter also snore and grind teeth during sleep. She is now 5 years old and her tonsils are actually blocking 90% of her airway and she is now scheduled to have a surgery and remove the tonsils.
Initially, my pediatrician told me that her tonsils are big, just wait and see if they will shrink or she will grow bigger. But my dentist referred me to a ear/throat/nose specialist. As soon as the specialist saw her, he told me they have to be removed immediately, because only 10% of airway is left. Very dangerous.
I suggest you ask your doctor or even a specialist for their opinion.