How to: break up???

I am a freshman in high school. this is my first relationship and we’ve been dating for three months (three months on tomorrow). i really liked this kid but for a day or two ive been very bipolar about our relationship. he is very immature and it really annoys me sometimes. he does things to try and be cool and sometimes it just annoys me. i want to break up with him but i’m torn on how. if i do it in person it’ll be hard because he can’t just hop in his car and drive away. if i do it over text i’ll be rude. i’ve been thinking about doing it over facetime. some of my friends say it’s okay but others say it’s rude. i’m scared to break up with him because i don’t want to hurt him. but i don’t want to stay in a relationship i’m not 100% on. please help me i don’t know what to do!!

edit::

sometimes he does things without even telling me! about a weekend ago he went to Washington DC with his family and i found out via snapchat. i feel like as his girlfriend i should know these things, especially when he’s gonna be gone for a whole weekend.