Is this a cacuts or a palm, what is it's name?

Hi!
We've had this plant in our yard for about 8 years. We don't know what it is, and have moved it once because we saw another one in someone's yard and we saw how BIG it could get. It's been amazing and beautiful and an interest to everyone who walks by it, and we have no idea what kind of plant it is, let alone the name of it. This week, we noticed that it was growing a cone in the middle, which is a first, it's never done this before, and we wonder what is going to happen next.
Thanks for your input.
tg

 

That's a flowering stem coming up there. It'll flower some time in the next month or two.

 

Something like a Nolina or Dasylirion.