Again, be sure to keep up with the treatments & CPT. My son is also 3 years old and was diagnosised at 2 months . We've had our typical CF ups & downs. Always go with what you feel your child needs at that particular time & don't back down. The doctors do know what's best fro ypur child, but sometimes you have to be persistant with the nurse. I'm a nurse myself & sometimes we forget that everybody is an individual. You as a parent will begin to know day to day as to how your child is doing. Don't second guess yourself & you'll both be fine!!!