The definition of how old you mean:
“The number of years that a person has been alive.”
In other words, how old you are is simply the number of years that have passed since your birth. So, if you were born in 1990, as of 2019, you would be 29 years old.
It’s common for people to ask each other how old they are as a way of making conversation. It’s also a way of finding out if someone is old enough to do something, like vote, drink alcohol, or rent a car.
So, the next time someone asks you how old you are, you can give them a straightforward answer or share a little bit about your life story. Either way, they’re sure to be impressed!