Will I stop caring as I get older?

I'm in my 20s and every night, I start to get preoccupied about my time. Day by day, I get older and start fantasizing how I would die. Would it be painful or painless?

Past billion of years, we did not exist, and today we have been gifted with this life.

Close your eyes, in the next billions of years, there's just nothing. And in billion of years, the universe will end. ... Nothing will be left.

I kind of do not fear the next billions of years of nothingness, but I fear how I would transition to it day by day... until my death.