Non stress testing bc of maternal age

Hilary
I'm almost 31w and doc wants me to have a non stress test in 2w bc of my age. The doc has always been non chalant and don't worry about this or that even tho I'm high risk for GD, preeclampsia, and early labor. How many of you have had this test based solely on maternal age? And no other reason. I get the feeling there is something he isn't telling me. He recommended it after not being able to find her HB right away.. When he found it he asked four times about her kicks and movements. He said her HR is fine, not to worry. Then wanted me to have the test bc of my age (41y).