Someone said that the actor playing Robin Hood looked too young.
Until reasonably recent times, young people - especially young people of the nobility often shouldered their adult responsibilities young.
Ie, Catherine Howard, Henry VIII's fifth wife was only 15 when she married and him, and only just 16 when he had her executed. And of course, there was Lady Jane Grey, 16 when she was executed.
Okay, these two women/girls were probably little more than pawns in political power games, and had little real power of their own.
During the War of the Roses, the leader of the Yorkist side, Richard Plantagenet, was killed in battle [and had his head displayed on York Gate], and his oldest son, Edward took over leading the Yorkist armies. He was still in his teens. In less than a year, he had taken power,and was crowned as Edward IV. Admittidly, he had experiences advisors such as the Earl of Warwick [known as the 'Kingmaker']. But still, Edward was already an experienced soldier and leader who had done more than his share of fighting and commanding armies.
Some years later, the Earl of Warwick, who had helped put Edward on the throne turned against [probably because while he was negoitiating a good royal marriage for Edward, Edward went and secretly married a woman of comparatively humble birth. It led to Warwick's international humiliation, and after that, he was not a happy Yorkist] So, he went over to Lancaster. The upshot of it was that the Lancaster armies attacked England, and Edward had to go into exile in Burgundy
But within a few months, Edward had managed to retake his throne. At his side, and commanding a lot of his troops was his younger brother Richard, Duke of Gloucester. Richard was barely 20, but like his older brother, an able soldier and leader.
Richard was later to go on to become the infamous Richard III. Whether he was guilty of all that he was accused of is another matter, and one that will probably be discussed until the sun explodes.
Then he accurately throws a very heavy sword I don't know how many feet to knock two guards. 
