What is your normal BBT?

Alison • 37-married 3.29.15-in nursing school-11 yr old stepson-finally pregnant with our first baby together!
I just started taking my temp first thing in the mornings this week and my temps have been in the 96.8 range. That seems low but it's been consistent. Could it be low because I sleep with my mouth open?!  Should I wait a few minutes after waking before taking it?