Чему научишься в молодости, то знаешь и в старости

Skill and knowledge you acquire when young are retained till you are old

Cf: What is learned in the cradle is carried to the tomb (Br.). What is learned in the cradle lasts to the tomb (till the grave) (Br.). What is learned in the cradle lasts to the grave (Am.). What we learn early we remember late (Am.). What youth is used to, age remembers (Br.)