1st time para sailing!?

You won't get the same dropping sensation as on the roller coaster. On the coaster as you go over the top and begin to descend you have the weight of the coaster and everyone else on it propelling it down. On the para sail or a parachute for that matter it's only your weight pulling you down, and the parachute will be pulling you back up. As long as you're sure you're not afraid of heights you should be fine.