Personally I go as low with my sensitivity as my movement is not hindert.
"Not hindert" imo means that I am able to achieve a 360-400° turn from the left to the right side of my Mousepad comfortably
So normally I would suggest to use a higher sensitivity if your 360° turning-range is affected, but in your case you are still new into using a mouse for gaming.....
My tip: stay with your sensitivity for some more time, and if you notice that your arm mobility for big swipes doesn't improve over time, use a higher sensitivity!
btw, 75cm/360 is definitely in the extrem low sens segment