The "Careers" and "Specializations" of Force Users are very peculiar. In particular, each career area has a specific fighting style associated with it, which may be selected as the character's specialization. For more information on these careers and specializations, see page 66-98 of the Core Rule Book.
Additionally, any character may be Force sensitive, regardless of their career. In time, such a character may learn to harness the power of the Force. In other words, if you'd prefer to have a more grounded career as, say a Mechanic or a Rebel Soldier, you may do so and pursue learning in the ways of the Force on the side.