Is it normal to be scared of heights because i think i'll fall

I'm scared because I think whatever I'm standing/sitting on will break and then I'll fall to my death.
Even if I'm in something that is typically very safe. Ferris wheels and roller coasters are absolutely horrifying, and I don't mean just the lanky ones from carnivals, but also the ones that are major tourist attractions and need to be very safe.
A year ago, I rode on the large Ferris wheel that's right next to Niagara Falls. I was with several of my close friends and we were in an enclosed compartment thing, but I was so scared, my heart was beating the whole time and the scenario of the thing we were sitting in falling kept crossing my mind. I was too scared to look out the window. I couldn't believe my friends weren't scared.