First of all Arabians mature very slow and should not be ridden until they are at least 3 and then lightly. So at this point you should be working him in a round pen or arena only. Are you planning on gelding him? If so, it's time to do it. If you don't have good reason for keeping him as a stallion, then he should be gelded right away.
When I say good reason I mean that he is of exceptional breeding and/or you plan to begin a breeding program with him as your founding sire. And if he is not of near ideal temperament, I would think twice about keeping him intact. You want to pass on good temperament, as well as confirmation and style in a horse's progeny.
You might want to look at the Varian website to see what Sheila Varian says about stallions and their temperaments.
The Ten Commandments (for breeding Arabians). When it comes to breeding Arabians and horse sense in general she is a goddess! (Notice, small "g"!)
Arabian stallions are not a cake walk, even for the experienced horse person, so think long and hard about your plans and abilities.