Is this the start of Male Pattern Baldness?

Hey guys. I’m a 21 year old male who woke up today and just realized I feel like I’m losing my hair. I have extremely thick hair, but it seems like my hairline is giving up on me. I’ve really never noticed it until today. Both my grandfathers had hair and never went completely bald, and my father has hair at 57, albeit getting thinner. What do u guys think? Could this be my mature hairline coming in?