What does being an adult mean?

I'm 20 and honestly I don't really feel like an adult compared to when I was a teen. I have a job that pays decently well and I live with my dad to help him with bills and stuff since he can't afford to pay for them by himself and he also has dialysis and is overweight so I often have to help him do stuff like putting his socks on for him and stuff like, but I've been doing that since I was in high school and I feel like my life hasn't really changed all that much ever since I graduated high school. Maybe I was expecting more or something?