I just don't know what to do with my life

I'm 20 years old, I know for some people that might sound young, but for me, I feel old. I feel like half my life has passed me by already. Now it's just like what's the point. If I ever do find something I want to do, it would take me years of education, and by the time I finish and graduate or whatever, I'll be so old it would've made everything so pointless and it would've been a complete waste of time and effort. I don't want to spend half my life trying to be something that's inevitably never going to happen.