Your sister isn't Kevin Durant, by any chance. :-) No idea if this phrase was originally his, but it is often attributed to him.
fortune favors the prepared mind
Is a very similar sentiment but suffers from use of the passive voice. It is a thing that is very obvious in hindsight, but isn't very, I don't know, motivational?Reframing it into the active voice is a worthy goal, and this version I like better.
> Hard work beats talent when talent fails to work hard.
To reach elite levels you need both.