You've done a good job at shading the values to make them consistent throughout each shape! However, I do agree that there is an issue with the values - I think your values are a little too close to each other! Your dark midtone especially looks like a shadow to me, though that's my personal interpretation. I can see you've tried to make sure each shape is distinct, which is great! But be careful with those outlines - they end up affecting the values on either side of them, which might be contributing to the issues you're having with those. This is especially true with the highlights. As others have said, keep proportions in mind in the future. But for a first attempt at this project, you've done quite well! Make sure to watch the demo now to compare and contrast what you've done.