Is being selfish for your own good is actually bad?

I am 22 working in city rn, i got my first job 1 year before. And i am living with my sister in the city currently. I had a good relationship with my parents my whole life, but it changed after my sister outed me to them right before i joined my job. I always knew no one in my family would accept me for being gay when i initially discovered i just like girls when i was 16, but now, since they have found out about this they keep pressuring me into marrying a guy, every time i go home for festivals or for any work all they do is talk about a suitable man. In the beginning of june, 2 weeks ago from now my father called me out of nowhere, i don't talk much to him after they have found out about my sexuality, and he gave me a deadline to say yes to the choice of his guy for marriage, i tried to postpone the marriage talk since almost 10 months by saying 2 years later, after i do my masters and other stuff cause i was just 21 then, but things have gotten worse almost out of hands since june, both of my sisters they don't support me and won't support me and i am extremely alone without any support from family, one of my cousin supports me but she's just 20 rn, and she can't do anything to help me.

I am going to my hometown today after 9 months to have "the talk" with my parents. But the problem is my dad got sick in may start, and somehow, now i am being blackmailed with his health. I deeply care about him, and i sincerely want to support him financially, i tried to tell him that the last time we talked, but he's very adment on not listening cause he's very patriarchal and homophobic, he believes life of a woman starts after marriage itself. And altho i love him very much, him and my mother both of them, i can't sacrifice my life for their happiness. It's like the sole purpose of their life rn to get me married off, I am not sure how the conversation with them goes, honestly. But i just hope his health doesn't worsen. I hope i can move out from my unsupportive sister's house and get a place in sharing with someone. Idk if this makes me sound very selfish, but i can never marry a man, I'd rather be ded than that.