"I may be young, but I have been playing Test cricket for more than six years. I also led my team for two years in the national league," the 22-year-old middle order batsman said.
"I think age is no bar for being a successful captain.
"Quite a few players have led their national teams even at a younger age than me," he told AFP.
Ashraful promised a new era in the country's cricket and has the ability to be a successful leader.
"I cannot express fully how happy I was when I heard that the board made me the new Bangladesh captain. It's a great honour to lead your country and it fulfills my lifelong dream," Ashraful said.
"I am ready for the challenge. Suman Bhai (former captain Habibul Bashar) has brought a lot of successes for Bangladesh cricket.
"I just want to continue that trend and bring more glories for the country," he added.
Ashraful will lead the Tigers in a three-Test and three one-day match series against Sri Lanka later this month, and has been named captain until the Twenty20 World Cup in South Africa in September.
Young paceman Mashrafe Mortaza, 23, who had a brilliant World Cup and an impressive all-round performance against India when Rahul Dravid's team toured Bangladesh last month, was named vice-captain for both Test and one-day sides.
Ashraful, who hit the headlines in 2001 by becoming the youngest centurian in Test cricket's history, was last month named the new vice-captain of Bangladesh after a brilliant performance at the World Cup where he was the highest scorer for Bangladesh.
The stylish batsman hit 87 runs from 83 balls to lead his side to a stunning victory over South Africa.
However he has often come under fire for performing below his potential since making a dream debut against Sri Lanka in 2001, and just when Bangladesh thought they had found a gem, Ashraful failed to maintain the consistency required to become a great player.
After playing 35 Tests and 101 one-dayers, his averages still remain in the low 20s and on Sunday he said his immediate goal was to improve his batting averages.
"I know if I fail to deliver as a batsman, the captaincy would not mean anything.
"My main duty is now to score consistently in Test and one-day matches."