Charlie Sheen is now officially the coolest grandfather-warlock on the planet -- TMZ has learned, his 28-year-old daughter Cassandra Estevez just gave birth to a baby girl named Luna.In borderline poetry, Charlie tells TMZ, "It's impossibly a most wondrous day. My bucket list is a thimble!"The thimble metaphor is subject to interpretation, but it sounds like having a grandchild was one of the biggest items on Charlie's bucket list. In other words, the rest of his bucket list is so small, it's thimble-sized. But our guess is as good as yours. Fun fact: Luna has two uncles who are only 4 years older than her ... Charlie and Brooke Mueller's twins.