Carlton Cole admits he has had to improve his time-keeping since becoming part of England's plans under Fabio Capello.
The West Ham striker knows the clock is ticking in the battle to be part of Capello's squad for the 2010 World Cup finals, if England secure qualification.
Cole once showed up for a match at half-time during his Chelsea days, and concedes he was immature and not professional enough in his approach.
But that is all behind him now and Cole is keen to make an impact under Capello after impressing as a substitute in last month's friendly against Holland in Amsterdam.
Ahead of the friendly against Slovenia, Cole said: "My time-keeping is still not that good. I once turned up for a match at half-time early in my career. I'm not proud of that. I realised that being on time is a big part of things.
"I realised I wasn't punctual enough but, when I come to the England camp, you've got to be punctual. It's your neck on the line. Fabio doesn't stand for it and he will embarrass you in front of your team-mates if you're not early for something.
"On my first trip, I got a bit of a tasting (rollicking) but I'm not telling the story of what happened. I'll keep it between myself and the team. I wasn't professional during my early career. I just felt that I had to change. Something just clicks in your life and it happens.
"There wasn't a low point that made me decide to do it. It was always going to come. It comes at a stage in everybody's life and career. Everyone changes at one stage, that's how it happens.
"The early Carlton Cole was young and immature but now I've matured and I know what I want in life and I'm going to go for it and I want to continue to be involved with England.''
Cole has been on the receiving end of some good-natured stick from Jermain Defoe after his back-pass gifted the Tottenham player a goal in the recent clash between Spurs and West Ham.
That cancelled out the elation Cole had felt at scoring a superb goal in the same game for the Hammers.
Cole said: "Those things happen. It was an individual mistake, a moment of madness and I just know I won't be doing that again because I don't want to be feeling like that again, the feeling I experienced when I did it.
"I just felt so gutted when the pass went to Defoe's feet. I knew it would go straight into the net once he took hold of the ball. He's given me banter about it and hopefully I can play him in like that for England now. That might get me into the next England squad!''