Any suggestions?

She is quite well lit, your photographic technique is good, although she may be a fraction too pale. Any editing in Photoshop, or simlar, is invisble, which I am becoming known to prefer for most people photographs. I can think of at least one person, Adam, who will be amazed to read the above about the lackof visible editing. Very well done on that last point. The colour works well but IMO the choice of such a coarse textured jumper, or whatever it is, is distracting and not supportive of the sexy theme. The fact that it is also a richer colour just adds to the level of distraction it provides. Her natural apperance, wearing no make-up, is a good call and the eye contact is perfect, as is her expresion. Bottom line, she looks lovely and apart from the choice of knitwear and the very slight over exposure, which I am sure can be corrected in lightroom or photoshop, you have together made a good photograph. You ask, Is it a beauty portrait? Not sure. It has a touch of that but also a touch of sexy glamour portrait, if there is such a thing. More importantly it is a beautiful portrait.

So what to suggest as a way to addres the the knitwear and make it look a bit more polished? I am better at experimentation than theorising. So I did some work and then made a it slightly higher saturation than yours (which looks more like a glamour portrait) and another with slightly lower saturation than yours (which looks more like a beauty portrait). Have a look, and please let me know what you think.

Be sure to click on the images to see them at their best.
V1 with a touch more colour than yours. V2 with a bit less colour than yours.

Very nice image. I do shoot quite often with one light and prime lenses so this totally appeals to me. 2 things jump to me as things that could've been improved tho

First, the lines on her neck. There is only so much a model can turn her head without lines appearing on her neck due to skin folding. For this pose if it was me I would've get the model to tilt her head down as she turned to try minimise if not eliminate the lines on her neck. Tilting the he'd down slightly may help stretching the neck skin

Two, I would lower the light and perhaps move it a bit closer to the model. The aim would be to minimise the shadow under her nose which makes her nose appear larger than it is and also to try eliminate the shadows on her back which makes it look like she has a lumpy back. A reflector to fill the shadows also is needed to help with those 2 problems further.

There is a 3rd thing i could pick on but haven't and that is the color. To me her skin has a slight yellow tint but i am not going to say it is a problem because i don't know if that has been on purpose or not. If that yellow cast is not intentional then you may want to adjust it or not depending on the mood you want the image to project.
For the rest I really like the image, I am not bothered by the jumper or the the textures of it, I even think it is a nice contrast agains the softness of her skin. Definitely a very good effort overall. Is is a "beauty portrait" you ask? I probably would call it just a portrait :)

It's a good base to start with as a beauty shot. I love the pose and the position of her hands.

If you want to show more details in the face, then I'd suggest a closer crop.

Lighting wise, it looks great and there are some great tones there.