Any reason why you didn't 'square off' the final completed stitch?
I see your first image (on the left) was a little high. You'll get better at it as you do it more often.
It is a nice job for your first attempt.
Some suggestions: Before you take the first photo, hold the camera up, and pan the scene for the full scene you want to capture. Make sure you won't be needing to point the camera up or down as you go left to right. You want the exact same angle for each photo.
Also, as you 'pre-pan' for the final image you want, see which part of the image you want to balance exposure to. Set your exposure to that 'view'. When doing a stitch, the camera does not change exposure settings. All images are captured at the same exposure. In your case you set exposure based on the first image at the left, which made the middle part of the photo slighly overexposed. It would look better if your center section had a better exposure, and then your edges were a little darker.
Once you've got the view you want, then make your photos for the stitch. For the finished photo, you'll want to square it off after you've completed the stitch, so remember your individual photos will be a little shorter in the final image than they are in each individual image.
Hope these hints help. If you make another stitch, come back and post it.
If you have any specific questions, post back or feel free to PM.
Bill