Don't consider it an age then, think of it as "the count of calendar years within which a person has existed." A newborn has only seen 1 year, 2023. An infant

Don't consider it an age then, think of it as "the count of calendar years within which a person has existed." A newborn has only seen 1 year, 2023. An infant born any time in 2022 has lived across 2 years. This simplifies things when you only need, or only have, someone's year of birth.