Yachty Boy,
I was 110kg when started, and learned on a mate's 165lt Starboard Go, then got my own 165lt JP excite, both excellent boards, and more than big enough for someone like me with no sailing, or surfing experience, I'm now generally on a 135lt board, but lately having a blast on a board that matches my weight in litres...
The fact that you have that experience with balance, and rig handling, means you could prob go a tad smaller than I did (150lt ish?) A mate of mine has recently taken it up, he's also a yachty, and races 'Cats', and although he's only a lightweight (80kgs) he's progressed from a 111lt 'carve' to a 99lt, and is keen to go smaller. My point being, once hooked (and in the harness/footstraps), you'll be wanting to get on the smallest board possible, but a big board is a good investment in getting through and enjoying the learning period, and also comes in very handy later on for those light-wind days.