Chaka is a lil’ long in the tooth to become a momma again,

Chaka Khan just signed herself up for the most stressful years in a parent’s life — agreeing to take permanent custody of her 10-year-old granddaughter … TMZ has learned.

According to new docs filed in L.A. County Superior Court, the order went through Wednesday — granting Chaka permanent guardianship over her granddaughter Daija Jade Holland. Chaka’s sister Tammy McCrary was awarded co-guardianship.

TMZ broke the story … Chaka won temporary custody back in September — claiming the girl’s parents (including her son) are drug addicts … and are incapable of taking care of her.

A sad story … with a happy ending.

It’s good that Chaka is stepping up to the plate to take care of her son’s daughter. Cocaine is a helluva drug…SMH