My Mother did the same thing with my brother and I when my Dad and Uncle were diagnosed as T2.
We both had low readings and when she asked the doctor about it he said that normal young people can get lows without any problems and that it wasn't a sign of anything to be concerned about. That was 30 years ago, I've gone on to be T2 and my older brother hasn't. I suspect because of genetics because I look more like my Dads side of the family than my Mother's. My older Brother, who looks more like he belongs to my Mother's side of the family, has shown no signs of diabetes or insulin resistance. Mom's side of the family has no history of diabetes in her family... just alzheimers and heart disease.
I can't help but think that I may have the better of the genes available but only time will tell.