I am thinking this is the newer way of reporting ANA, as far as I know anything under 100 is normal. There's another way of reporting and that's in titres which you will often see here. They double each time, 1:80 (low positive but enough for diagnosis if there are lots of signs of disease and criteria met), 1:160, 1:320, 1:640, 1:1280, 1:2560.
There's more to diagnosing than the ANA though and many of us were negative early on like you, then it changed. Is your doctor doing more follow up on you?