A strong attempt for a novice, yes. An above poster is correct. You're beginning to pay attention to how the body works. Your eye needs a bit more training. Before I begin to break down the attached red line I have provided, a general tip to help you immensely as I have notice you are drawing digitally: flip your canvas on occasion. In PaintTool SAI it is the H key. This will help you see your drawing at different angles and it exposes glaring flaws with an immediacy that will feel as though you are looking with a new pair of eyes.
Getting into this, I want to approach your more glaring struggles in this image. I have put green numbers on the redline, Going down the list...
1) Her shoulders were misaligned. If you were attempting coy body expression, it could work. But you must keep in mind how the rest of the body moves in tandem with any tilting shoulders. But for now, I went for the easier route for you. If you want a level body at a 3/4 forward facing angle, it would save much stress to map out the chest proportions almost identical you would the face and head. The dotted blue lines across the chest are angled slightly to denote the subtle turn in the body and will aid in showing where the shoulders rest and where other areas are going to fall behind. The clavicles (which I should have put in) then go straight across the chest almost perfectly horizontal just above the pectorals. Take a look at medical diagrams of the human body or fitness models to understand further how the muscles group and lay over the skeleton.
2) The breasts, I won't sweat you over this as most people would online and discourage you. Breasts initially seem quite difficult, but some basic principles will have you adept at them quickly. You have the right idea of the basic form of breasts but there there is a tad more nuance to placement and shaping you could employ. For starters, on a fit body body shape like this, breasts at the size you have will almost always begin at the pit of the deltoid. The blue dotted circle I have is an indicator to show where the arm should be placed and where the breast can start. Use the chest construction lines (the blue dotted cross in the torso I've placed) to level each breast evenly. Finally, you will always hear that in many cases, a basic shape to use is a slanted "tear drop" shape, or ovals. From there it's refining. This is especially going to take some long term studying. You cannot shirk this.
3) For the third point, refer to the visual tutorial I have placed on the right. The seven step head guide. This is a very crude, stylized, but effectively simple means of achieving a very elementary cartoon anthro head shape with all of the proportions in check. Do not swear by this as like I've mentioned it is stylized. But learn from it. Use it as loose reference for how to proportion the facial features with ease. I would recommend you study human and various animal skulls/heads.
4) Yes, as mentioned the neck is rather long. If you look at how I've built the neck, you will surely notice a shallow triangular shape of the muscles. These are large muscles forming mostly towards the back of the neck called the Trapezius (root word being Trapezoid which is a major shape of the neck that leads into the deltoids). It smooth transitions into the classic cylinder shape which is a relatively stunted shape at the angle and head tilt you have. Try to look at back muscles and replicate to understand how this works!
You will notice a theme among all four points. I want you to practice and study. Reference photos. Copy master sketches. Draw a life model. Build up the muscle memory and mechanical skills required to understand and recreate these shapes and anatomical structures on a whim. You will only progress with these intensive studies. As I've said in point 3, do not swear by this as it is stylized, but use it as a spring board to further understand where you could improve.
You've an appealing start here. Continue practicing.
EDIT: I apologize. I got sidetracked in my home when writing this just as I was going to write the general tip I mentioned and just immediately moved on without typing it down. I've now added it.