The prolific attacker made his first-team debut in the friendly game against Porto on November 16, 2003, and he has stressed that it was a dream come true for him to join up with the senior side at the tender age of 16.
"November 16 2003 is a very important date for me, because that’s when I was able to make my childhood dream come true," Messi told Barca TV.
"It was a very happy day for me. I’d fought hard to make that moment happen and it was really special.
"I remember that we were training with the Juvenil A team and, when it finished, [academy co-ordinator] Josep Colomer talked to me about a few things and then told me that I would be travelling with the first team.
"He told me that I should just go and enjoy the game and the experience, but when I came back I should concentrate on the Juvenil A team."
Messi has since gone on to develop into Barcelona's undisputed star player, yet he has stressed that his success has not changed him.
"I think that I continue to be the same person. I see things in the same way, though I have grown and learnt how to value things."
The Argentina international, 26, is currently sidelined with a hamstring injury and is set to be out of action for the remainder of 2013.