First of all, im on mobile and this is my first post on this sub, so sorry for any formatting mistakes. Also, probably gonna be a long post.

Background info: my cousin was born in the U.S. so he's a citizen by birthright, but he was raised in Mexico and lived there for pretty much his whole life up until a couple of years ago. He came for vacation in the summer one year, went back and came for vacation again the next. The second time, he stayed so he could go through high school, so he's lived with us for 2 and a half years.

So my cousin (M18) just turned 18 2 days ago. I'm 16M and share a small room with him and my youngest brother (8M) (too small a house for 7 people). He's done a lot of things that bother me, and im sure I've done things that probably bother him too, and he might even be able to tell i get annoyed at him. One thing is that he always likes to call his "girlfriend" late at night as im about to start sleeping (around 10:30). He knows damn well i have  a 0 hour class everyday, making me get up at like 5 every morning. (Girlfriend in quotes because i think he might be playing her).

Another thing that bothered me was when i went on vacation to mexico a year ago, he was there along with my other younger brother (12M). So when my cousin first went to my High School, me and my Girlfriend (17F) were the first people he sat with at lunch while he met people and made his own friends. Anyway, i see him as a player/fuckboy. In Mexico, he and another cousin said they knew a girl my age who's single and According to them, super pretty. They wanted to set us up together im pretty sure, which i didn't like at all. The cousin i live with kept trying to pressure me into it, basically saying "you need one for mexico and one for the U.S." and it annoyed me and i pretty much said "no im not a fuckboy like you" but in Spanish. He finally stopped after that. There are other things he does that really bother me (leaving used, wet towels on the floor of the room, spending sometimes up to 20-25 minutes in the bathroom, etc.)

So the day of his birthday, my mom reminded me to tell him happy birthday a few times, but i never really did. I felt kind of bad about it but i feel im not obligated to tell him happy birthday if i don't want to, so AITA? 

tl;dr: My cousin who irritates me and i think he's a little bit disrespectful to me recently became 18 years old but i didn't say happy birthday to him.

(Also, idk what tl;dr stands for so someone pls tell me lol)