If a 12 year old has eat raw chicken will they dies ?

No: no they will likely not die, but they should be monitored for illness, diarrhea, vomiting

Unlikely: Raw chicken can be contaminated by the germs that were common in their poo, like e.coli,Salmonella, Shigella. These can all cause a diarrheal illness and or other complications. With good available health care , the chances of a kid dying from exposure are almost non-existent.