Cool Mark that you got yourself a studio set-up!!
And with a cute gal like that to pose for you, how can you go wrong?
Exposure-wise they look "real" enough, as in skin-tones appear to be probably what you'd see with your naked eye and you have deftly avoided any skin-shine or over blown highlights.
As you are not using reflectors yet, it might help to move her a little further away from the muslin to avoid the shadow in the first one - not that the image suffers from it.
The background is a little "uniform" and drab and although it help separate your model and create more focus, tossing a little more light around can help create some interest, if you so desire.
Portraiture in a slightly formalized set-up as yours is often - not always - done for the purpose of bringing out the best or flattering the model. Your gal doesn't need flattering as she's cute as a button already, so I mean in general.
For example: in the first one, the Directionality of the light suggests that it's up and to the left of the camera. This can cast unflattering shadows on a face - like my own weathered mug. Dropping it a little can fill out the natural shadows a little and make it appear more vibrant. Experimentation is key.
I know that you're not make a Revlon advertisement where everything is so forcefully lit that skin looks like orange plastic, but there is something to be said for a very gentle raise in the warmth/yellows of the image. You can do this with gels, filters and post-processing, for example. However it's a very personal taste kind of thing and some portraits are designed to be "real" as opposed to "flattering".
In the first one you may have more of her delightful face to enjoy of she turns a liiiittle to the right - or you more a little to the right with the camera. This increases "intimacy" so that the beholders feels more like being connected with the scene/model.
The second one seems a little more like a "snap" and less a formal portrait. There's some "centrism" going on there with perhaps too much air on both sides. Compare that to the third, where she fills the frame and you have a little more "interest". It's fun for sure, but with her eyes covered, distance is created and not enough personality is conveyed. If you'd give her a camera with a viewfinder to the side and with her other eye open looking at you, for example, you could retain the camera and increase "connection" to the model.
I like the last one too. It is very expressive and conveys that little-kid fatigue that every parent knows can set in at a seconds notice..lol. It could also be interpreted as "sad" or "unhappy" or "frustrated"..all strong.
As a series, I'm left with the desire to see her face, her eyes and her full expressions - to get a glimpse or sense of her personality expressed through her face rather than her body-language. There's a hint of roguish charm to her, but it's not fully expressed and I think you and her can create some really strong portraits if you let us see more of her eyes and face.
Being far from a portrait-photographer myself, take all I say here only as personal observations on my part - evident of my own taste and preferences rather than any kind of expertise
Thank you for sharing these images and I hope that you will share more with us soon!