little holiday help under 18s

[lpb-nissan-gt-r]

Well the story is, the school has planned a school trip to china for 1400 pounds. and some of us thought this was just too expensive, so we are getting a group together and hoping to go to Portugal next summer, as a group we are looking at either renting a villa out or going to a hotel i'm personally leaning towards a villa as it will give us more of a community feeling.

We have chosen Portugal becuase a its nice weather
Drinking age is 16 we are not just stupid drunkerds we drink responsibly and are looking to have a good time and stay safe
It'sin europe
We all agree on this destination

Now I would like some advice on some planning and things that I may need to look out for etc. one question I do have though are adults under 18 allowed to stay in hotels without an adult?

All help is appriciated.

Paris.