Gosh that is a tricky one =X
I think it depends on how happy I am at the time. For example... if I was to be told around now I'd want to know. Why? Well lately I've just been loitering around the house. Not being too productive. Knowing that I'm wasting my life but being to ignorant to change that. If I only had 3 weeks to live and I continued to just waste it like that I would be incredibly upset. To think I could have been living life to the fullest instead of being on a diet and wasting my time.
But. If I was happy... as in doing all of the stuff I want to. Surrounded by my friends and family... then no. I wouldn't want to know. <3