My Daughter Has Been Diagnosed With Adult Onset Partial 3

My daughter has been diagnosed with adult onset partial 3 beta enzyme congenital adrenal hyperplasia. She is 31 with a high stressed job as a court reporter (where she can't ask to take a break when she needs one) and owns her own farm where she cares for 3 horses she trains in Dressage. She is highly active and busy 5am to 9 pm or later. Her doctor put her on metformin as a first line drug. She has not tried steroids yet. I am worried because her blood sugar is normal, can be low and her BP is low. Should I be worried about her being on Metformin?