Is it normal to develop a fear of something overtime?

For example when I was younger I used to love going to knott's berry farm. My favorite ride was jaguar and montezuma's revenge and ghost rider. Now I would be scared to death of those rides even the slowest one(jaguar). I been on a boat when I was little but I'm pretty sure I would get sea sick If my current self were to go on one. I also developed a fear of heights. I didn't have that when I was little but one day just magically "lol your scared of heights now".  I didn't have any traumatizing experiences either, the fears just happened