Marsh has endured a stop-start international career that has seen him fail to realise the talent many observers believe he possesses.
Since making his Australia debut in 2008 the Western Australian has managed 41 one-day international appearances and seven Tests.
It is a record the 30-year-old admits would have been better but for inconsistency, while injuries have also frustrated his ambitions.
But after seeing the likes of his former WA team-mate Chris Rogers, and Australia Twenty20 skipper George Bailey, become key figures in their thirties Marsh suspects his best cricket is yet to come.
"Oh definitely. You look at a lot of the players now who are playing international cricket, they are all over 30 and they're playing really well," he said.
"We've got a lot of players in our team as well who are world-class players over 30 so there's still lots of time.
"But I guess you've just got to take your opportunities when you are this sort of age."
Marsh smashed his highest ODI score in his first innings after turning 30 - a bruising 151 against Scotland last summer - before a hamstring injury prematurely ended his series against England.
After then missing Australia's seven-match ODI series against India in October, he has been handed the chance to again revive his career against England, starting at the MCG on Sunday.
With a World Cup on home soil just over a year ago, he knows he must start to take his chances.
"It's another good opportunity for me to play well and try to cement my place in the team - so there's lots to play for," he said.
"I've performed well at stages when I've played for Australia so that gives me confidence.
"I've just got to be a bit more consistent. If I do get an opportunity I've just got to grab it with both hands.
"There's a lot of good players around Australia at the moment who are scoring runs and applying pressure on us guys who are in the team."
If Marsh is given his chance it is unlikely he will return to the top of the order - where he batted in the summer - following David Warner's recall.
Warner is likely to open alongside Aaron Finch, but Marsh is confident he can perform a role in any position.
"I think so. I'm pretty flexible in the batting order," he said.
"I can bat down the order if that's the role they want me to play.
"Over the next few days I'll get an understanding of whether I'm in the team or what sort of role they want me to play."
England have opted to rest Stuart Broad for the opening two matches of the series - to allow him to recover after the Ashes - which initially leaves them with an inexperienced bowling line-up.
Marsh rubbished suggestions the tourists' attack was 'pop-gun' though with the likes of giant-sized duo Steven Finn and Boyd Rankin in their ranks.
"They've got some really tall quicks, Stuart Broad and Boyd Rankin and Steven Finn as well," he said.
"They've got a really good attack.
"We're going to have to work out how to play them and have our plans against them and be nice and positive against them."