yucca

Hi I moved into a house in Spain 6 years ago and it had what i thought was a yucca tree 2.5 to 3 metres in height in garden. It is now about 6 metres high. It has 3 main stems. 2 stems have 3 smaller stems coming off each.
The third stem goes straight up. I would like to cut all stems back down to about 3 metres. I have attached some photos. First question: Is it a yucca or a palm? second question: would it survive if i did cut back to 3 metres? I would welcome any advice or suggestions.
Thanking you in advance
Regards
Atajoman

 

I'm guessing, but it looks like yucca elephantipes .

So you can cut it back to where ever you like it will regrow.
You might want to reduce the amount of new shoots it makes though, so as to stop it turning into a large green mass.