I think it's true. Captain America could have picked uo Thor's hammer - but I think he didn't do it for two reason. One reason is yours. Another one is - HE FELT NOT READY.

According to Joe Russo, Captain America had the power to lift Thor’s hammer in Age of Ulton, but pretended he couldn’t to keep Thor happy.

Yeah you can't be "almost worthy" in magical terms. If you're not worthy, Mjolnir won't budge.

It's true, The Russos confirmed it, and Joss Whedon confirmed that that was his intention with that scene in AOU.

Yea it’s confirmed

This is from a QnA on Reddit with Feige

Yeah. It’s actually confirmed in the movie itself since Mjølnir briefly budged.

It’s a fact actually

It is true. I remember finding this out a while ago and I still love how wholesome it is. :)

Oh okay, i guess this was just what came up first when i searched it up