Well, for a first attempt, it's not bad, not bad at all. But there are some points that should be fixed. For example, the Orc development on the map is limited. They basically have no chance of survival, and that's not very good because it only makes sense to play as the hero, but even then, it won't be too difficult. But for a first map – bravo! Advice: you could close off the emptiness with mountains; it would look good.
I'll add that the map is too simple even on Hero difficulty. It lacks scripts and quests; the mission is too linear. But for a first attempt, it's not bad!