The feminine version of Milan, derived from the Slavic “milu,” meaning “dear.” And your little Milena will be oh so dear to you, even on those days when she’s being less than endearing.
Mili, Mila, Lena.
Famous people named Milena:
Actress Milena "Mila" Kunis; Miss Bulgaria 2008, Milena Sharkova; model Milena Toscano.
Milena is also a genus of butterfly - perfectly fitting for your little free spirit.