Hi Peter pan, my post wasn't about an be all and end all statement for a longboard, at your size and weight a minimal like Rickyrough neck said is a good option.
My statement about longboards was against the thought that they are as turnable as an aircraft carrier.
Things to consider; you have told us weight and height so longboard/minimal = good, you probably won't need to change boards for quite a while as the learning curve is better for having a baseline board and then branching out because then you will know you mind and in what direction you wish to take your surfing.
Usual progress, straight line to beach white water standing
white water standing minor direction changes all of which is no big deal just reasonably easy to achieve and often done in one day schools
the game changes catching a green( unbroken ) wave matching speed, dropping down the face setting a turn riding across the wave, crank up your excitement, this is the beginning of real surfing, here some of your board sports balance and skills may resurface and speed up the process.
Enemies of success, impatience and going to too small a volume board as unlike land boards, you need flotation for easy paddling, most beginners find the timing and skills of paddling and popping up the most difficult (Hence the mass of post on this). All multiplied in your case by the need to paddle in a severe wetsuit.
Keep us posted on board choice and progress in a cold climate.
