Hello!

So this is probably super weird, but I just don't know how to stop thinking about it. See, sometimes I get a little jealous of my younger sister for a few reasons, but I love her so of course I just brush it off in a healthy way bc I'm still on my self love journey. But right now (I think because my period is coming) I can't help but wonder if the guy I'm talking to has ever been attracted to her solely on the basis on that sometimes he likes her twitter selfies and that they're closer to the same age. Some background is that we all went to the same high school, so we all knew of eachother. Obviously, I don't wanna ask him bc I feel like this is such a weird thing to worry about, but the fact of the matter is that i am and I'm not sure what to do. Any guidance out there?