Are humans acrophobic in nature?

I think I am acrophobic. Whenever I’m on higher ground and looking down I would be afraid and that will petrifying me legs. This is,however,different for my friend,she can sit on the top of wall of 100ft building (without fence) without worrying about her possibility of falling down. Most people are like me,on higher ground they just look for a while and turn around or quickly walk away to safety zone.

I think most of us would be naturally afraid of height whenever we’re on higher ground but not some who are accustomed to this situation. So,are we really acrophobic in nature?