I don't think that this fear is all that
uncommon even among,.. as you put it, "Thrill Seekers"!
I'm scared shitless of heights, yet I do Love to do some rock climbing! Top rope, bouldering, and LOVE rappelling!! But I'm fuckin' paralyzed up on a ladder! I did Roofing in S.Cal. for 5 years after getting out of the service. Used to climb 2-3 stories up 'n' over the back of the forklift to get up on the roof. But standing at the edge, made me freak!
My first 5 or 6 rides up the high speed @ boyne, I nearly shit myself cuz NOBODY
was putting the freakin' bar down! Not even little kids!!! All I could think about was how many bones were going to shatter if I slipped or fell off this thing! And near as I can tell,.. Boynes lift ain't SHIT
compared to some of the lifts in places out west that I'm dyin' to get to! But you know,.. after the first 2 or 3 dozen rides, I don't even notice it anymore!!! If it stalls, I light a smoke & enjoy the scenery! (...for about 3 min. then I'm screaming 'n hollerin' that they're wasting my ride time!!!)
As for the steeps,.. so far nothing I've been on in MI. has been high or steep enough to freak me just by looking down it. Now RIDING
down it, that's a whole other type of (mostly newbie, not got the skills kind of) "Freaked"!!!!
You seem committed enough to the sport to keep at it, So I'm sure time & experience will get you past the fear.