Is it normal if im scared my bf will like my sister more?

Okay this is weird, delusional BUT you never know it could happen. When I met the guy I'm seeing right now I knew he would fit in my life perfectly. He just reminds me of a part of home. So ya that's a good thing but then as we kept dating, I noticed he has A LOT in common with my older sister. My sister and I are a like so that says me and him have those things in common but theirs is like on another level. I feared introducing them cause I just thought he would not only see me in her but in addition to all their similarities. Finally they met but it was brief. I do think tho that my sister thinks he's cute. I know it. What doesnt help is hes older than her so it makes even more okay. She has a bf who she loves very much tho so ya there's that but that doesn't stop feelings. From their style to their taste in everything. Part of it is yes cause they're about the same age and he's five years older than me. I think they grew up more around the same era but I kno its not a huge difference from me but still. I mean what could suck even more than having your sister/brother be a better match for the one you love? Its like I would like to see them get along but were pretty similar that they would get along on a different level. I just feel like I have to get rid of him for the better but then I know I shouldnt cause of that. Its scary, its a bummer, it's stressful, sad, etc.