harassment in the work place?

I'm 16 and have been working in my current job for 6 months and recently have met one of the owners close friends he seemed okay at first enjoyed a joke here and there but then as more and more staff left the room he would make more and more sexual remarks. Until it was just me and one other member of staff the same age as me left in the kitchen when he made a comment about my bum. Now this man is old enough to be my dad and these comments made me feel highly uncomfortable I have scince spoken to my friend who also said he made comments about her too. I feel very uncomfortable in my work place and am unsure what to do.