Should I get my dog fixed?

Wait until he is six months old, then get him fixed. It is healthier and will lead him a longer life if you do not plan to breed or show him. His personality wont change if he is not aggressive or marking territory in the house or anything like that. It does calm them down and prevents some things and also almost reduces some things by a ton. it will also be easier for you to train him and build a better bond with him because he will be more focused on you and less on the urge to mate.