Hi! This is a wonderful start!
Before I talk about your piece here, I want to mention some good artist habits that might make it easier for you to make artwork down the line. I can see where you are drawing right on top of your sketches with the ink. There is nothing wrong with that, BUT I have found that it actually makes life MUCH easier down the road if you use a lightbox to ink your lines onto another piece of paper, therefore preserving your sketch. That way you can always make tweaks without losing your original sketch. Also, it makes your final work look cleaner in the long run without you having to worry about erasing the lines and maybe accidentally smudging ink or ruining the paper. I can see that you did some thumbnails at the top, but I also think doing more thumbnails would probably be a good idea. I always try to shoot for at least 10 where I rotate the "camera" around the scene to find the most interesting view. I can see that several others have mentioned that so I wont harp on this.
Onto the piece:
The griffin and the rider have wonderful expressions. I like that you are varying the line weight between thick and thin. moving the griffin away from the tower a bit will help this to read better. Working on larger paper will help you do this. I always sketch in a 14x 17" sketchbook so I have plenty of room to stretch out. Or drawing smaller on the page you have would help as well. Also, eliminating most of the lines around the stones in the tower will help clarify the image a bit as well. You only need a couple here and there to suggest that the tower is made of stone. Having the lines from the wings over the lines of the stones makes a bunch of visual noise that makes it harder to read. I think adding shadows will help you clarify the forms in this.
I think you did a brilliant job overall! The story is clear, the characters are engaging, and you are already developing a look for your work with the linework. Keep it up!