Is this skirt too short?

So I bought this skirt for my birthday. I turned 18 a days ago. I've never owned a skirt before and thought this whole outfit looked very cute. I wore the skirt with a similar sweater as this one out, and I could tell my father wasn't happy about it because of the length but chose to ignore it because I felt pretty. But then I overheard him make a comment to my mom about how the length of the skirt was only appropriate in a pr*stitution place or something like that. I think he was kidding but honestly I don't know. For some background knowledge, I'm also 5'9-10" and my legs are definitely the longest part of my body. So is the skirt really that short? Please be honest here, I really do want to know.