The Oldest Is Always the Favorite?

So I think my parents really like my older sister way more than me. It's just a feeling, but there are these little things that make it seem true. Like how she gets to go on fun trips and I'm always left behind to help around the house, or how they never check if I did my homework but they always know when my sister didn't do hers. And then there was this one time, we both got new phones as a birthday present, same model and everything, except hers is unlocked right away while mine takes forever for approval from them. Maybe it's just me being paranoid or something, but sometimes I wonder if having been born later means you're never the favorite. Do other youngest siblings feel like this too? Is there anything I can do to change how my parents see me? It feels kind of unfair.