My older siblings were slightly better students in terms of stats.
One of my parents went to a Most selective or highly selective sub 20% school. Each my parents got something like your Sam thank you so much for encouraging Sam Junior to apply he will be given every consideration. For Sam 1 this was a low match and he went elsewhere. For Samantha this was a high match and she also went elsewhere. Samantha visited and considered it. For me it is a low reach. Based on that they know both siblings turned them down will it hurt me?
First of all, there is nothing you can do about it so don’t worry about things out of your control. Second, I think the school will evaluate your application and make an admission decision on your own merits, not based on what your siblings did.
Another poster gave this advice to someone in a similar situation, and I think it is wise, so I will pass it along.
Probably they will not take note of your sibling relationship unless you have an unusual last name or a famous parent. So you might be best off not calling attention to it and just being judged on your own merits.
If and only if it is one of your very top choices, another option would be to mention in your “why this college” answer that you visited it with your siblings and loved it and were surprised when they did not choose it. You, on the other hand, would be ecstatic to be admitted.
Or, better yet, apply early decision. Applying early decision will remove any doubts!