Different tack: What do you want out of windsurfing? It seems you are young, keen and a quick learner with very good sailors around to help you progress fast. With that in mind I would make the strongest recommendation possible to steer clear of anything like a 110-120L free-ride or cruising board because you will out grow it super fast and you will be bored as ****. This is unless you are happy to cruise back and forth for the next 5 years just working on gybes...sounds boring right...it is.
If as I imagine you want progress your windsurfing to the widest range of possibilities; proper board/rig control, waves, freestyle, general bawse spec then as I stated before get a 100L (ish) freestyle board, you will NEVER out grow it. Most people dismiss them because they have never tried them but mark my words, this is THE board you want if you want to progress your windsurfing as fast as you possibly can and have nothing board wise holding you back. The only thing is they are harder to find, heaps of freestyle waves, not that many freestyle boards. TBH i'd ignore any FSW boards, they are a compromise, never ridden one that i've though, **** yeah.
Maybe a touch big for your weight (but ok), something like this
www.seabreeze.com.au/Classifieds/Windsurfing/Boards/~bu7ci/2009-JP-Australia-Freestyle-Pro-107-230-cm-108-litres.aspx?search=8x7uhC3xupLfSeSIUroV8hgQM09lGfgE