Every day of your life has an exact length of daylight, set by where the Sun stands above the place you live. Pick a city and a birth date to see the curve for your first century — from the longest day to the shortest, from birth to today.
The calculation uses the Sun's real position — declination and the equation of time — for any date and any coordinates on Earth, not a table of remembered values. It works as well for the year you were born as for 2120. Times are calculated for the true horizon, with the standard correction for atmospheric refraction; they can differ by a minute or two from a local calendar because of surrounding terrain.
Cities come from a public database of more than 34,000 places (GeoNames, CC BY 4.0). The century shown on the timeline is illustrative, not a prediction of how long you'll live — just a window wide enough to watch the seasons shift around you, year after year.