Heights have never been a problem for me, but as I am aging, I am finding that I get nervous with heights. The sinking feeling disturbs me now, almost causing slight dizziness/nausea. I used to be able to go on roller coasters, but now I am finding them to be very intimidating. Must be the age, because I can't put my finger on anything else.
I don't mind heights as long as they're moving fast - for example I'm happy to go in a roller coaster but not too keen on cable carts. It doesn't stop me from going on them, I just don't enjoy it as much as doing other things.
I used to enjoy roller coasters, ferris wheels, etc. As I grew older I found I couldn't tolerate heights. Indeed walking along castle walls overseas made me feel as though I wanted to throw myself off so started having a panic attack and had to get down to ground level quickly. Still can't take heights at any level.