Lol - I like the drawings on the blackboard!
Nice work, okyatoks.
The celshading is good. However, you forgot to shade the floor!

And I suggest you use another color for the frame on the left picture. Because it is so agressive and "hurts the eyes". Something more subtle like with your right pic will fit better.
You can improve your shading by using more shade layers.
Anyways: good work!