Truthfully, Bjoern has been playing football since he was 13 or 14 years old. He played with a club in Berlin, beating up a bunch of players that were much older than him, and then found an offshoot NFL program that gives scholarships to kids around the globe to come to the US and play prep football when he was around 17 years old. I think it's a little bit of a myth that he's not been playing football very long because truly unless you're a quarterback then if you've been playing since you were 13 or 14 then you've been playing as long as anyone else just about. The most impressive thing about his background and "lack" of experience really is just the fact that as a 16 year old kid he went out and created his own NFL future. He did everything himself. His Berlin coach merely suggested that he should go to the states and play football, he didn't do anything for him. Bjoern went out, found the program that gives scholarships, applied himself, got in touch with prep school coaches and secured his spot in a prep school, and made sure he could pay for everything himself...and THEN he presented the idea to his parents, who were mainly concerned that they didn't have the money for all of it. He assured them he had all that taken care of and all they've had to pay I believe was for his plane ticket. Some time later, he married his high school sweetheart from Germany.
The whole back story is the kind of thing NFL coaches and scouts eat up. He's been acting like an adult far before the time when other guys start acting like an adult (if ever).