Not bad for a first map. There isn't a whole lot wrong with it visually. The textures are aligned correctly and match nicely. You have decent lighting, there is not a lot of really dark spots.
However, I think it's a little too empty. The pillars only offer so much cover, and there is no cover on the top level. Maybe add some props or something to add variety.
That said, the map is balanced and a good job for a first map. Keep it up.