Honestly, when I ride it I can never tell it's high up until the doors open at the top, but that's only for a second or two. If you're nervous about the heights, just close your eyes.
The worst that could happen by going on it is you ending up not liking it. It's not a long ride and it only drops you a few times.
Last year my friend was absolutely terrified to go on it. She almost used the chicken exit, but we pushed her to go on it. After the first ride she was still pretty scared, but after the second or third time she rode it, she completely relaxed and still talks to this day about how it's her favorite ride at WDW.
As I said, the worst that could happen is you not liking it. Might as well give it a shot.