Hello and welcome to the guild!
Crtics: I really like the mountains, they give a very good height feeling. They could use a bit more of texture, tough, but I'm not certain about that.
What needs improvement are the rivers. They look as if they are carved out with a one size pen (which they are I think), then there are these white lines in it which is very irritating. And the northern source of the river that comes from the mountain in the north west looks as if it flows up (Actually I think you began with this river and then you became much better in drawing them).
All in all I would say it's a great first try.