It’s easy to see why some people are scared of horses. After all, isn’t a Shire Horse much bigger than you are? Despite the fact that some horses kick or bite, most don’t, so there really isn’t a need to be scared of horses. Often it’s caused by a poor memory in childhood, though it can also be caused by your parents being scared of horses.
Probably your best bet is to go and have cognitive behavioral therapy. Most phobias don’t go away on their own, so waiting won’t really help.
If this therapy is done correctly, you will not be scared of horses anymore and may even consider getting them as a pet if you end up liking them enough. See What do I need to keep a horse? for more information.