First, can you position the sconces on either side of the mirror, toward the top, where there is more space? Either way, here are some ideas:

(In each example, the mirror is approx. 2/3 the width of the countertop.)

One chandelier--good for limited space on either side of mirror.

Pendants--gives the look and feel of sconces but saves space.

The color of your mirror depends on your preferred color scheme. To keep it simple, you could do a wood frame or a frame that matches the finish of your plumbing fixtures.

Thank you! I have a pedestal sink which is making it harder for me. I found a mirror that is 25" do you think that is big enough?

That is plenty big. You could even go down to 23" at the widest point.

The sink is 28" wide, I found another mirror that is 30" is that to big?