Don't force yourself on to anything! It's your vacation too, remember?
I'm not a big ride person myself, I am terrified of heights. However, last year I did attempt a few rides that ordinarily I wouldn't have. Mostly because my husband kept hounding me or using his "reverse psychology" and the fact that I can't let him best me.
So, here is a list from a chicken, of what I went on (for the most part, I might forget a few) with a rating for each.
Pirates of the Carribean - NOT scary. Even the unexpected dip, which did make me cry out "whooa", was really not scary, just unexpected.
Tower of Terror - Okay, I spent the whole ride consoling my terrified daughter.

All of the pictures that they show you after have me keeping her from freaking out. It IS a scary ride, there's no doubt about it. I don't like the big drops. However I did survive and bought everyone a t-shirt afterwards because we were all brave enough to do it.
Dinosaur - IS intense, but that's the dinosaurs not the ride itself. It's bumpy, shaky, etc. but I don't recall any huge drops or speeds. It was a very cool ride.
Expedition Everest - SCARY but exhilerating. This is the first roller coaster I'd been on since I was 13 (which was my very first time on the biggest coaster in Canada at the time at Wonderland). How they ever got me on it I'll never know, but I did. And yes, it was scary. But I was glad I did it. That was one I was proud of myself for going on.
Test Track - NOT SCARY in the least. It was cool, no major drops. Just some speed.
Soarin' - NOT SCARY and I'm terrified of heights. It was quite relaxing.
Space Mountain - Kinda Scary cause it's in the dark. Actually, the swift turns hurt my neck! My kids went on this about 10 times. Once was plenty for me.
Astro Orbitor - SCARY. And ONLY because of my height thing.

The ride itself is quite tame. It's being on the roof of a building that I didn't like.
Buzz Lightyear - Loads of fun, not scary at all. We did it a couple of times.
Mission Space - I didn't do this. I like my lunch where it belongs, in my tummy! My husband did the high impact one, not realizing there were two to choose from. He loved it but said he'd never do it again. It was too intense on his body.
Peter Pan - NOT SCARY. A relaxing and whimsical little ride.
It's A Small World - VERY VERY SCARY. It's like a little bit of hell that ride. Not because of the boat or anything. It's the creepy little dolls that sing without moving their lips and the constant repetition of the song that drives you insane.
Thunder Mountain - NOT SCARY. If anything, you'll get whiplash but you won't be scared!

Very fast, so fast you blink and it's over.
Splash Mountain - I didn't do this but my son and husband did. My son (9 at the time) thought it was the scariest ride he'd been on at WDW. And since he rode just about everything including every mountain, I'd say it's scary!
Fortunately, there are so many neat things to do at WDW that keep your feet on the ground you'll have a wonderful time whether you conquer every mountain or ride. Just have fun and stick within your comfort zone. It's a vacation, not a life or death challenge!
