He was not 17 when he set up another shell company in Panama:

Mega Star Enterprises, the offshore company owned by Messi and his father at least as far back as 2013, is not mentioned in the Spanish government’s 2014 and 2015 indictments against the pair. The leaked records show Messi signed at least one document reflecting his ownership of Mega Star

http://indianexpress.com/article/sports/football/panama-pape...