I live in South Florida and I dive a pinnacle 5mm cruiser(old name for the elastiprene model) pretty much year round. I love my suit. I have worn it in waters down to 60*, and have been toasty as a bug in a rug. I do suggest either trying one on at a shop, or ordering one from a site that offers free exchanges on sizes. I only say this because, when I ordered my suit, I was smack dab in between a small and a medium, according to the sizing charts. I ordered the small. When I got the suit, the small was WAY too small for me. I upgraded to the medium size, and it fits great, but even that is a li'l tight on the surface. Once I'm in the water, it is as comfortable as you could want.
I would suggest getting a 5mm model instead of the 3mm. You'll have more flexibility, IMHO. Like I said, I dive my 5mm in South Florida most of the year. When I do switch to my 3mm, it's more because of the heat on the surface than the water temps. Nobody likes overheating while waiting to hit the water.