ADO Den Haag
Toornstra was born in Leiderdorp. In his youth, he played eight years for amateur football club Alphense Boys in the Tweede Klasse C. In his last year he scored 20 goals for the team. He impressed so much Kees Jansma recommended Toornstra to ADO Den Haag. Initially, the scouts of ADO Den Haag did not believe Toornstra would be as good but ADO Den Haag bought Toornstra for the reserve squad.