For a beginner, nice job. Take what I'm going to say with many grains of salt. I don't earn a living with my camera, haven't official credentials, and don't have anything posted to illustrate how little I know about photography OR art. I've just been shooting a long time and have looked at lots of images.
First, the image is largely monotone on my screen - a more or less medium dark flesh tone. The lightest spot of skin is at the "corner" of her left hand - to the right of the ring. I think you wanted the RING to be the center of attention, but the eye tends to go to lighter areas - so the light spot on the hand competes with the ring for attention. If you had arranged the lighting so that the "mini-spot" had hit the ring, it might have been more effective. Likewise the bright spot behind the subject should have been flagged off. Learning to see everything in the frame BEFORE pressing the shutter release is, for me at least, a continuing struggle.
The ring itself is just a bit below the center of the frame. There's a rule of thumb, called the "rule of thirds," which basically says that placing a visual point of interest along the vertical or horizontal 1/3 or 2/3 lines is generally preferred over placing it at a 1/2 line. I think if you had included a bit more of your model's upper torso, so that the ring is about 1/3 up from the bottom, would have added a bit of strength, a bit of tension to the composition. Of course, there may have been concerns about showing private areas, which is understable when one is working with nonprofessional models. However, I don't think that would have been an issue here - you only need to add a little at the top to move the ring to the lower third.
Lastly, the lighting seems a bit flat. If the spot of bright light had been on the right, it might have emphasized the right effectively, but as it is, I don't think the ring jumps out visually enough to make a strong image. You could opt for a brighter and more sculptural quality to the lighting, but that would make this less about the ring, I think.
I like the quite, calm, yet sensuous, quality the image has.
Thanks for sharing.
"Keeping shooting will do more for the excellence of your photography than most any camera will!" JimmyD, PGS Extraordinaire.