Level new job?

[Holland]

I wonder if its possible to level the new job through exp points(from level 1 to 50)?

You can only unlock jobs when you have the main class for it at level 30. From then on, if its feasible, you may level only using your job and all exp goes torwards your class. You should not think of a Job in FFXIV as a separate entity but a "Mode" that your class enters.