The circular bed of gravel and fire table are in a nice, harmonic rhythm with the shed and lawn. I think I would leave leave it just the way you have it.

Your picture doesn't show the left side surroundings much. If you wanted to curve the background bed line concentrically so as to coordinate with the circle, I think that would be fine, but agree with K&D that the grass surrounding the fire pit area is good as is. I would not bring taller plants closer to the fire pit ... there have only grass or LOW groundcover. I would bring the flagstone path all the way to the circle. It should end up with no trip edge. Since the edge sticks up all around, I'd flare the lawn & path up to conceal it.