We had rhubarb crumble on Monday, never too early for me. lol :O)

Definitely not too early...

It depends on how long the rhubarb has been growing for, ie if its been in its growing place for less than 2 years and you start taking sticks off it then you'll kill the crown,
its not whats on the top thats important but how well the crown is.
GOOGLE rhubarb and see whats what ref this plant.

If its a new plant then only harvest at most a 1/3 of the stalks. if its well established go for it. I have taken stems before leaves have opened. in fact must pick some soon. Space in the freezer i hope.

OK, thanks all, appreciate your answers. WIll now brave the hail stones - yes, like golf balls at the end of April we have hailstones, bright blue sky and fluffy white clouds and hail stones all at once, me thinks someone somewhere is slightly confused!!!!!!!!!!!!!!!!!!

I would never take more than a third of the stems at any one time regardless of the age of the crown - just wait for another lot to grow. We've had crumble twice already - yum.