Every time I like someone they end up liking the same girl

I (16F) havent had a crush on many people in my life, I havent had my first kiss and I've never dated anyone. Of course I have liked some people but the past 3 people I told someone I liked, they end up liking this other girl (let's call her olive (16F)).

The first instance was the first time in a while that I had a proper crush on someone and decided to tell my friends - including Olive. He (18M) was in the year above me so i didnt see him too often but we started talking a bit and I went to the same club as him (by coincidence) so we sometimes talked there aswell. It got to a point where one of our mutual friends (who he didn't know were mutual) asked him if he liked me and he said he did but he was too scared to ask me out. The next day I tell Olive that he said he likes me and she was very exited. But by the end of the next week I got told by the mutual friend that he no longer liked me and thought we were better off as friends. Then I get told by one of my other friends that him and Olive have started talking and they bothed liked each other (they talked much more than me and him did).

The second instance i started to like this boy (16M) in my class and I told a few close friends - not Olive this time. We were talking for a while then he starts to become more dry. Then one day the people I sit next to in that class start telling me that they think he likes Olive and start asking him a bunch of questions and he starts to blush. Then when we go on a trip he is flirting with Olive the whole time.

The most recent time was when I liked this boy (17M) from outside of school and I told my friends - including Olive because she doesn't know him. Then one time when me and the guy I like were hanging out i was talking about something and Olive came up so I showed him a photo of her and then I find out later that he added he on Snapchat and was talking to Olive and really liked her.

Am I overthinking this? Is it bad luck? What should I do?