Yeeeep, there are Dragoons in this game. The quest to get the Dragoon job is one of the hardest though, so I hope you can find some good friends to help you out
You should know that you won't be a Dragoon till you hit level 30 on one of the six starter jobs, so you'll have plenty of time to think about your subjob, although I recommend Warrior. Hope to see you on the Seraph server

Hehe, I deleted my level 30 War / 15 Nin on Ragnarok because I realized a little late that Mithras are better for the jobs I'm interested in. Ranger / Ninja