I'm the Middle Child Struggling with Sibling Dynamics

I'm the middle child in my family of three. There's a five-year gap between me and both my siblings. Sometimes I feel like an afterthought. My older sister got to do everything first, so we ended up living entirely different childhoods. Now that she’s gone off to college, I sometimes find myself trying to copy her achievements just to get more attention from our parents, but it never feels genuine. Then there's my younger brother who seems to naturally have the easy-going relationship with both of us and the adults in the family. He gets away with things that would drive me insane if I tried them. Is this all normal? Should I just let go of trying to compete or copy someone else’s path and find my own way?