B.C.
These are great, very easy to make and so addictive!
http://www.eaglebrand.com/recipe-detail/magiccookiebars-3934
It'll last for a few days (weeks actually) in the fridge for you to gather ingredients.
Condensed Milk Expiration Date
(Unopened) Pantry
Past Printed Date
Sweetened Condensed Milk lasts for 1 Year
(Opened) Refrigerator
Sweetened Condensed Milk lasts for 2-3 Weeks