I have some mixed feelings about what happens as we age. On both sides of my family, my grandparents were sharp until they passed. Three of the four were alive until their 80s. I think how mentally sharp we are depends on how well we take care of our bodies and minds.
Subsequently, you made some excellent points about relativity and the speed at which the world spins. I recently read a scientific article claiming the Earth has been spinning faster and faster for the last 15 years. Earth's speed has never been this high. Perhaps that could be the reason the days feel shorter than before.
Overall, well done, and great job with creative storytelling! I couldn't tell it was your first time. Thank you for sharing!