Hart is currently on loan at League One side Port Vale.
He told ESPN: "There was a bit of indecisiveness going on at United and I managed to get a trial down at Liverpool.
"Mick Beale was the U16's manager at the time and he likes attacking players, and I'm that kind of full-back, so he liked me and I moved to Liverpool.
"I wouldn't change anything about it. Moving to Liverpool was one of the best things I've ever done."
Liverpool's coaching staff welcomed Hart with open arms, something the youngster will not forget in a hurry.
He added: "It's such a big club and as soon as you get there and meet all the staff and the players, you fit in - and that's the thing you go for. I was ecstatic to join Liverpool."