O'Brien, 36, is part of the 14-man squad to face England in the first ODI of the three-match series that is scheduled to be played at Ageas Bowl on Thursday.
O'Brien wrote his name into Irish cricketing folklore with a magical innings against England in Bangalore during the 2011 World Cup as he smashed a 50-ball century to set up a historic three-wicket win.
"It's coming on 10 years now," he said as quoted by ESPNcricinfo.
"It's a little bit frustrating. It's obviously a very proud thing, and to talk and think about it does give me goosebumps. But I'd like to think I've had some performances since then to not just go back to one game.
"Whether my scores show it or not, I think I'm a better cricketer now: more rounded, with more experience under my belt. I'm certainly in a better space now; a more comfortable space with where I am mentally and physically," said O'Brien who has played three Tests, 145 ODIs, 96 T20Is for Ireland.
"There's four or five players all around a similar age," O'Brien said of the younger crop who have shown promise... "and for them it's a great opportunity to write their own legacy and write Irish cricket's next chapter. The hunger's certainly there with the young guys to get better, train hard, and be the best players that they can be.
"Ultimately it's up to them to bring Cricket Ireland forward when myself and a few of the older boys hang up the boots. We've brought it as far as we can, and it's up to the younger guys to bring it even further.
"It's certainly something that I've taken notice of over the last 14 or 15 weeks, over lockdown -- a few areas that I need to improve on to stay a step ahead of the younger guys. That's great to have for me as an individual, and from the team's point of view if we're all trying to be better than each other, ultimately the team should be in a better place going forward.
"The competition for places is crucial and it's important that we have as much depth as we can. People are only going to experience that by being thrown in at the deep end and playing games like this and learning on their feet."