Roy Hodgson named a number of youthful talents in his World Cup squad, with Ross Barkley and Raheem Sterling's displays among few positives as England suffered a worst ever tournament campaign.
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"Time is running out for us to say we're young anymore," Wilshere told reporters. "It's easy for me to stand here and say, 'we're young, we can go forward'.
"If you look at Germany, they've got young players who are delivering now. I'm 22, Ross, Luke [Shaw] and Raheem are young players.
"They showed in this tournament what they can do but, in the next tournament we really have to deliver. I'm not young anymore. I'm going to be 23 in January and that's a good age for a footballer."
Tuesday's 0-0 draw with Costa Rica signalled a worst points return for England at a World Cup and a first group stage exit since 1958, but Wilshere hopes the experience will act as a learning curve to the squad.
"It's all a bit raw. I'm devastated. When we get back to England then we'll wake up every day and think: 'what if this, what if that'," he continued.
"It is a nice group of young players and hopefully we can stick together, learn from this tournament, take all this disappointment and bottle it up. This is the worst feeling.
"What excuses are we going to use? We prepared well. We're just disappointed. It's all a bit raw. We'll wake up every day and think, 'What if this, what if that.'"