Is it normal that i think my moms high school boyfriend is hot?

Is it normal to be attracted to my moms old high school boyfriend? He's super hot and yes he's at least 17 years older then me but we have a lot in common and I think he caught me checking him out. He's one of my dads best friends but this is the first time I have seen him since I was like 2. We even talked about our sex life's and what my mom has and didn't do. He invited me to one of his parties should I go? My dad wants me to go