is it to late?

I have 5 Blue Mystic plants about three weeks into flowering and just found out my friend who I send my seeds to is moving and have no one else to send them to. So I am wondering if I can still take cutting off of them.

Sure you can. They will take an extra couple weeks to root but they do root.
I would take a few extra as you will probably lose 25% or so.

no, not at all......read this amazing article i stumbled upon, it kills alot of myths surrounding cloning flowering plants. http://www.420magazine.com/forums/seeds-clones-strains/56864-what-flowering-clone.html