(18F Throwaway account cause my other account is solely academia based lol)

My cousin (14M) from my mom's side and his family visited over this weekend, they're very conservative though it is common in the country i live in (third world).

My older brother (34M) is married to my beautiful SIL (33F) and they live in my house so they met up with my cousin's family too.

Now the problem started when after family dinner, my cousin pulled me aside to say and i quote, "I was not able to focus on the food today at all, SIL has some great b**bs" and he laughed loudly along with my father who was also present in the kitchen with us.

I was utterly disgusted and I left immediately as both of them made more inappropriate remarks (not just her but about other women in our house). It was bedtime and my mother said to share a room with my cousin but I disagreed upfront saying i didn't feel comfortable with him as he can't stop making sexual remarks on the women in our family.

Now im getting a lot of backlash from my cousin's family for hurting him, that he is just a kid and i have hurt his ego by saying that in front of both of the families (Called me a brainwashed feminist). Even my mother had asked me to apologize but i didn't as i had no reason to.

Now i get that my cousin has literally not even started to develop his frontal brain and i might have overreacted but it pissed me off big time that this was the type of guys i surround myself with. AITAH?

TLDR: cousin commented on my SIL's body so I disagreed to share a room with him cause he made me feel uncomfortable