Im making double fudge chocolate cupcakes

And I just realized my icing which has never been opened, still has the aluminum seal over it, is past date. 
It says use by March 2015, which is weird, because I bought it way after March 2015. Anyway, will it be safe to eat on top of my cupcakes? 
Like I said, it's never been opened, it's sealed shut with the aluminum. 
I'm 5w2d, and afraid to eat somethin past date.