DALE EARNHARDT JR.’s bride-to-be is begging the NAS­CAR champ to retire after he admitted that he kept a recent brain in­jury secret!

The 38-year-old racer an­nounced to reporters that he hadn’t told anyone about a con­cussion he’d suffered Aug. 29 in a test crash in Kansas.

Just a few weeks later – on Oct. 7 – Dale sustained a seri­ous concussion in a 25-car crash on the last lap of a race at Talladega Superspeedway. That injury forced him to sit out two subsequent races.

Although Dale insisted that he had fully recovered from the first concussion by the Tal­ladega event, his girlfriend of two years, Amy Reimann, was dumbstruck by the revelation.

“She wants him to retire be­fore it’s too late,” said an insider. “She doesn’t think he has any­thing else to prove on the track.”

Dale revealed that the con­cussion from the Kansas crash affected the frontal lobe of his brain and caused headaches, while the Talladega accident resulted in a concussion to the base of his brain. He admitted that the back-to-back blows to his head had left him “mentally a mess.”

“Amy is scared to death for Dale,” said another source. “She’s fearful the next injury will end his career – or worse. She dreams of having children with him.”

Insiders credit Amy’s influence for helping pro­pel Dale to one of his best rac­ing seasons ever. He scored 18 Top 10 finishes – his most since 2004 – and he broke a 143-race winless drought.

“These head injuries may have finally knocked some sense into him,” added the source. “Maybe he’ll follow Amy’s advice and try to raise some kids instead of try­ing to raise his standings in NASCAR.”