Why Captain America Couldn't lift Thor Hammer in Age of Ultron?

We are aware of the scene from Avengers: Age of Ultron where every avenger tries to lift the Thor Hammer ( Mjolnir ) and Captain certainly couldn't lift it. As the Mjolnir has odin seal from Thor 1 that those who are worthy can only lift the hammer. And that clears Captain wasn't worthy at the time in Age of ultron but suddenly at the end of Avengers: Endgame he did lift the hammer. How come he became worthy all of sudden? So here's a theory that explains what happened between Age of Ultron and Endgame that made Captain worthy. So back in Captain America:Civil War we knew captain knew that Bucky killed Tony's parents all this time and he never revealed. He carried the guilt with him all this time and even during Age of Ultron, he lied so he wasn't worthy. After civil war he doesn't have anything to feel guilt. He became pure again. He confessed to Tony. ...