what make u good in l o l

Sorry if this is in the wrong place. Im new to this forum. So, recently my friend and I got L o L, and we started to compete. However, he and I both have the same total kills despite me playing more games. He claims that kills make you better. This sint to solve our argument, this is just for me to know whenther or not kills determine your skill level. I have way more assists, just saying