I have a slightly different perspective from Crazy. IMHO, a bigger board is better, especially if you will be sharing it with tentative wife and kids. A big board will make learning easier and light wind sailing more fun, and it will work just fine in strong winds, too.
I would definitely not go any smaller than the 170 liter GO, and might actually consider going bigger (200+ liters). Also, a board with a retractable daggerboard will give you more versatility in light winds, and help you get more time on the water for practice. If you are planning to do lots of sailing in winds less than 15 knots, a START or RIO might be a better choice than a GO.
Hope you get a chance to get on the water soon.