Eleven players have made 10 appearances or fewer for England, which plays Italy in its first-round opener on June 14 and also is grouped with Costa Rica.
"Circumstances will prove whether the decision to take the younger player was right or not," Hodgson said during the squad announcement, held at a car factory in Luton, north of London.
"You get experience by getting the opportunity. It's wrong to focus totally on the fact there are those who are inexperienced because everyone is inexperienced until they get the chance to do the job. I think they've played so well and been so effective in their club teams that they've really imposed their ability on my thinking."
The most inexperienced player is 18-year-old Southampton defender Luke Shaw, who made his national team debut in March and displaced 33-year-old Ashley Cole from the roster. Shaw will be the backup at left back to Leighton Baines.
"He has had a wonderful season ... and is capturing the headlines with his form and ability," Hodgson said.
Nineteen-year-old Liverpool winger Raheem Sterling and 20-year-old Everton midfielder Ross Barkley, who total five international appearances, also were selected.
"He's a very, very exciting player, a very exciting talent and if he can continue at that level he has a very exciting future ahead of him," Hodgson said of Barkley. "But I would hope people will temper their expectations of him."
Hodgson picked four forwards: Manchester United's Wayne Rooney and Danny Welbeck, Liverpool's Daniel Sturridge and Southampton's Rickie Lambert. Lambert, who has two goals in four England appearances, helped push Toronto FC's Jermain Defoe and Andy Carroll to the standby list.
"I'm sure if I'd picked a squad after the final qualifier in October it would have looked quite different, but a lot of water has passed under the bridge since then," Hodgson said. "You can't ignore what people are doing on a week-to-week basis and your decision is based on who is the best man for the job."
The only player picked who isn't with a Premier League club is backup goalkeeper Fraser Forster of Scotland's Glasgow Celtic.
Goalkeepers: Joe Hart (Manchester City), Fraser Forster (Glasgow Celtic, Scotland), Ben Foster (West Bromwich Albion)
Defenders: Leighton Baines (Everton), Gary Cahill (Chelsea), Phil Jagielka (Everton), Glen Johnson (Liverpool), Phil Jones (Manchester United), Luke Shaw (Southampton), Chris Smalling (Manchester United)
Midfielders: Ross Barkley (Everton), Steven Gerrard (Liverpool), Jordan Henderson (Liverpool), Adam Lallana (Southampton), Frank Lampard (Chelsea), James Milner (Manchester City), Alex Oxlade-Chamberlain (Arsenal), Raheem Sterling (Liverpool), Jack Wilshere (Arsenal)
Forwards: Rickie Lambert (Southampton), Wayne Rooney (Manchester United), Daniel Sturridge (Liverpool), Daniel Welbeck (Manchester United)