I'm in TX, and I dive either 5mm or no wetsuit usually. Any further north, and definitely 7mm. Maybe even layering, with some wetsuit shorts or hooded-vest underneath. Even during mid-summer, when water-temperatures are 80+ at the surface, down at 60ft it's still cold.
It might be worth checking craigslist for used ones, obviously in your size.
If I get too warm in a wetsuit, I "flush" the wetsuit, by repeatedly opening the neck of the wetsuit to let water in/out.
If you get the wetsuit shorts + hooded vest, you could still use those in a warmer climate, if 7mm is excessive.