My younger brother keeps messing with me?

I'm 18 and he's 16 and he keeps on trying to fight me some reason. Yesterday I simply asked him if he can give me back my iPhone charger that I let him use. He starts saying that it is charger now and I have to take it from him. I didn't feel like arguing so I had just walked out the room.

And Today I walked we walked past each other and he just gets in my face saying fight him. So I told him to get out of my face. And then he actually pushed me. Which caused my glasses kinda falls off. So I pushed him back but I didn't really fight him because I'm the oldest and try to be the more mature one out of my siblings. He the 2nd born and I also have a younger sister and a even younger 9 year old brother that acts more mature than him!

I don't know what to do. I haven't fought him like 4 years and all of the sudden he wants to pick a fight. I have other things to worry about like graduation, college and I have issues my girlfriend so I just want him to stop but I want to handle it on my own. But I'm also thinking of telling my mom since I know my dad wouldn't care.

Hormones

If you guys are still living under the same roof as your parents tell your parents about it

I would tell your rnorn and it rnight help to rnove out so you don't have to deal with hirn

Yeah tell your mom

You are an adult at 18.
You can't assault and hit a minor… However you can restrain him if he tries to harm you. You can go ahead and retrieve anything he has taken from you without harming him and write your name on it. You don't have to put up with this and you can remind him that he is a minor child anytime he wants to take you on.

Give him a hard kick in the sacks, and walk away as he lies wimpering on the floor