The woman is celebrating her 26th birthday in 2020 because she was born on the 29th of February 1916.
The year 1916 was a leap year which means that it had an extra day on February 29.
Assuming the woman in question was born on February 29th, that means she celebrates her birthday once every 4 years on another leap year.
Since 1916, there have been 26 leap years including 2020. This means that in 2020, the woman would indeed be celebrating her 26th birthday.
In conclusion, the woman may be 104 years old (2020 - 1916) but because she was born on the 29th of February, she is only just celebrating her 26th birthday.
NB: The two words in question are Leap Year.
