The 33-year-old centre was a key figure for Andy Farrell's team during the recent Championship and is now targeting a spot at next year's World Cup in Australia.
McCloskey told The Daily Telegraph newspaper: "To do it at the age of 33 when probably a lot of people had written me off is special.
"When I was sticking around, that was always at the back of my head – that if I could get in for one bit and leave some kind of mark and someone might remember me playing at some stage, that was the goal.
"Hopefully it's something I can build on, I feel like I have a couple of solid good years in me. There is a lot of rugby before then, but I would love to go to the World Cup."
McCloskey was instrumental as Ireland achieved a record-breaking 42-21 victory against England at Twickenham during the Six Nations and the Ulster star recalled how he was fired up by a speech from Ireland's forwards coach Paul O'Connell.
He said: "The closer we got to the game, there was an emotional side to it – it's England, it is Twickenham – which was driven really well by the coaches, but it wasn't building up too much more than it is.
"Normally Johnny (Sexton) does a bit of a chat with the back before the game but he and Paulie swapped that day.
"We did it at our hotel before we left for the game. It was words about what it meant to them. It wasn't derogatory about the English, he read a passage out of a book that he had been reading, and it was really inspirational. All the backs loved it. Sometimes it is nice to hear a different voice in those meetings."