There is no reason to be scared because they are inspected at least every year so they are safe. Also, it is all the same movements as if you were in a car or plane and the only difference is you are outside.
Not only are they not scary, they are fun. You can go on a roller coaster an unlimited number of times and they will still be fun, I can't think of a boring roller coaster! Mostly because I remember their climax. Some speed up, some go upside down , some do both and much more.
Also, every roller coaster has seats right next to each other so when you ride on a roller coaster you are sitting next to your friends having a good time.
What part in my essay scared you? I thought those all sounded like good things.
Sam P.