Hi Julia
Good luck to you and Lanza is a nice choice but VERY different from Italy!!! There are quite a few Lanza sites, and many members are common to more than one of them so you will soon get to know people if you join - here are two to be going on with - and then there is this one too of course!!!
http://www.lanzarote.com/forums which has a chatzone section most of the members are very friendly and will offer advice and support. Some of them are Lanza residents....and I think quite a few may be within the age bracket you describe.
http://www.lanzaroteisland.com has a forum too, a little less friendly,I would say but nevertheless lots of the members there will offer help.
Good Luck and have a great time!!!!8)