relationship problems

So me and my boyfriends have been together a while, we have always had a thing for each other since 3rd grade. Anyways, we are currently boyfriend and girlfriend and we are at this point where we are starting to argue a lot. I know it’s normal to argue in relationships but our arguing is quit different. He often acts really immature and it’s embarrassing. That’s not his personality and I tell him to stop acting immature and he never listens and I always end up getting upset. I have terribly bad anger issues, I’m working on it. This will probably sound stupid but he always takes my stuff on fortnite, I don’t care to much but it still makes me extremely upset.But sometimes he makes me wonder if it’s worth it. I love him, he is the first boy I have ever loved. I don’t know what to do? I need advice. Btw we are 14. And I know people may say it’s not love but you guys don’t know me. It’s love I swear it is.