it's not totally since human years and cats are different
Each year of a cat's life is roughly equal to four human years, so a 3-year-old cat is about 29; a 4-year-old cat is 33; a 5-year-old cat is 37; and a 6-year-old cat is 41. And so on and so on. If your cat gets to 20, she's around 97 human years old