when does n. cantabricus usually bloom?

Hi,
About two months ago, I received my first batch of n. cantabricus bulbs and planted them outdoors. We live in Braunschweig, which is roughly between Hannover and Berlin. Outside temps are now around 5 to 15 degrees C. To my surprise, the first slender grass-like leaves appeared nearly four weeks ago. A couple of days ago, I noticed one or two shoots and I suspect those will be the flowers. — Is that the normal time for n. cantabricus to be making its appearance?? Have I done anything wrong?
Thanks, Niels