Hi Florina,
This song is primarily a 4/4 with the music retarding (musical term for slowing down) at several different moments in the song. The thing that should help you count this is listening to what the left hand is playing, which are the lower/deeper notes. It's definitely a beautiful song.
When I perform ballet and modern dance to songs without lyrics I learn the song inside and out, especially with classical music. This aides me greatly in feeling the music vs counting the music. This is one of those types of song that you will want to know by heart and how the music retards before picking back up. The other people posting are spot on with it being "open to interpretation and creative expression." You could definitely perform Modern, Ballet, & Contemporary to this.
Depending on how tech savvy you are and how much time, there are computer and phone apps that allow you to speed up and slow down the tempo of a song without it changing the pitch of the song. Certain apps also allow for you to save and burn it to a CD or an mp3. Doing this might allow you to create a specific tempo which will allow for a Foxtrot, Nightclub 2-Step or creative Bolero footwork (even though it isn't a Latin song.) Please understand that altering the retards in the music might remove the dynamics from the song that make it beautiful.
Hopefully that helps!