I don’t know which one I should do

Hello! I’m sorry if this is a silly question but I’m in a weird spot with my citizenship/passport and I’m not sure what to do.

Both of my grandparents are from Ireland and immigrated the the u.s. with my dad and his siblings. My dad was born in England.

I have my dad’s Irish passport and his birth certificate from England. I also have both Irish grandparent’s birth certificates but I do not have their marriage license.

I am not sure if I am already a citizen since my dad has an Irish passport and citizenship but was not born in England. But I have no way to recover my grandparents marriage license since it was lost by U.S. Immigration when they were getting their U.S. Citizenship.

What should I do? Should I attempt pursuing a passport because of my father or try and attempt a citizenship? Any advice helps!!!