Digital Art history has already been broken.

Hmm, I love the stock, very crisp and nice to look at.

The avatar is rather mild in terms of visual composition. I would personally suggest straying from putting the focus in the center. Putting her partly to the side and making the stock larger and more cut off will make it more interesting rather than a full front view. Glad you didn't use pure white as the background, that would distract from Yeul.

The signature... It's beautiful, I can't help but gaze into her eyes. I can't decide if having her in the center works, but it doesn't look too bad. If you were to add more to the background ever so slightly, that would help. But I think this can roll well enough as it is.

I see a trend in most of your work, you tend to use simplistic, tannish backgrounds and crisp, elegant stocked characters. I like your general approach, but if that's all you do, which is fine, I suggest looking for angles and extremities in your positions for the stock. Having it dynamic will make it far more appealing, rather than a still visual bog. Having flow will move the eyes, and that is key to visual simplicity with success.