Frank Dillane was 17 in Harry Potter and the Half-Blood Prince when he played the character 'Tom Riddle (16 Years)'.
That was over 15 years ago in 2009.
Today he is 33, and has starred in 9 movies in total, 5 of those since Harry Potter and the Half-Blood Prince was released.
In Harry Potter and the Half-Blood Prince, I think Frank Dillane looks: