the first hundred years are the hardest
A humorous phrase typically used as faux consolation, assuring someone that their life will get easier after they reach age 100. A: "Don't worry, honey, the first hundred years are the hardest." B: "And that's supposed to make me feel better?"
first hundred years are the hardest
Prov. The first hundred years of your life are the hardest, and after that, you can expect things to get easier; in other words, your whole life will probably be difficult. (A jocular, ironic way to console someone who is having difficulties.) Don't worry; things are bound to improve for you. The first hundred years are the hardest.