It is a good beginning, good for you on working to master a new skill.

As a semi-OCD person, I will offer some (hopefully) constructive criticisms. First off, the addition of eyelashes will make a big difference in looking natural. You may not have gotten that far yet but when you do, would like to see it. Secondly, I would suggest softening and reducing the shadowing in the upper part of the white of the eye. Too much shadow there leaves the eyelid looking like it is pulled out away from the eyeball. The addition of eyelashes will reduce that effect but the shading may still be a bit dark.

Age and sex of your model will effect how the brow line sits but my preference would be to see the brow line, particularly the part toward the out edge of the eye, be higher. The distance from the edge of the lid to the rear of the brow should be close to the height of the eye itself. Lastly, be sure your pupil is centered in the iris. The pupil in your drawing is slightly more to the right. This gives the impression the eye is looking off a bit to the right but if this were the case, the iris should be moved toward the right or the entire eye/face should be angled away toward the right.

That said, you have drawn a better eye than most people would be able to and continuing to work on your drawing will bring you nothing but improvement. Keep at it and let us see how it goes.

Where do you take classes?

It's pretty good. It looks a little flat? More depth would be good.
Still better than anything I could do, so I am impressed!

Is there a particular expression you are trying to convey?

Is there a particular expression you are trying to convey?

Is there a particular expression you are trying to convey?

Soften the lines inside the eyeball. Contrary to eyebrow and eyelashes missing. Normal eyebrow do not follow the shape of an eye, they are very expressive and independent from the eye. I am not an expert but I like to observe. Keep an eye on your work and like anything else you will get only better.