regardless of your petite stature, I would place the sconces centered 64" off the floor

center the mirror(s) over the sink(s) Generally centered with the sconces.

You'll still be able to look into the mirror comfortably, and the light from the sconces will be great. Do you have recessed lights in the ceiling as well?

if the mirrors are not a mirrored medicine cabinet, the height of the faucet shouldn't affest placement. If it is a medicine cabinet, the doors need to clear the top of the faucet.

We do have recessed lighting in the ceiling. The mirrors are not medicine cabinets, just mirrors.

I'm using 3 sconces. One in the middle, then to the left and right of the mirrors.

So you're saying center the sconces at 64" from the floor, and center the mirrors around the sconces?

Sconces are to illuminate your FACE to aid in shaving and applying makeup. So the position of the light is what's important not the length of the sconce.

I typically set sconces from 60 - 66" above the floor to the center of the fixture. If you did 65" , then it would be centered on the mirror if you set it about 9" above the countertop.

Because it is a tall fixture, you could go higher but I don't think I would go lower.

I should have noted this. The light is the full length of the scone. See photo (not with the mirror I'm going with), so also posting my 20x40 mirror if helpful.

The mirror is 40 inches tall. 9 inches above countertop seems high for 8 ft ceilings, but I'm not a designer, so expert help is appreciated!!!