My position is linebacker.
Linebackers are defensive positions in football. How long have you played football? 
I have been playing since I was 6.
So how many years is that? American football positions have changed over the history of american football. 
That would be 25 years.
Have you ever played rugby? American football and rugby have many similarities. 
No I have not.
Early history of American football
The early history of American football can be traced to early versions of rugby football and association football. Both games have their origin in varieties of football played in Britain in the mid–19th century, in which a football is kicked at a goal or run over a line, which in turn were based on the varieties of English public school football games.
American football resulted from several major divergences from association football and rugby football, most notably the rule changes instituted by Walter Camp, a Yale University
Karl Brill
Karl Brill was an American football player. He played at the tackle position for the Harvard Crimson football team in 1904 and 1905 and was selected as a first-team All-American in 1905. As a sophomore in December 1905, Brill announced that he would not continue playing football. He said, "I came to Harvard to get a degree as a mining engineer. For the last two years 'Varsity football has played havoc with my studies. Already I have been forced to drop work in my