Hello,
How old are you ?(that also counts ;) )
If I was starting SUP, I'd go for a 10 ft x 29" to 30". This option not only will let you have some performance and forgiveness to progress, but most of all, will be a great backboard for future smaller summer days. A keeper.
If you're on europe I'd suggest "GONG SUP 10'0 NFA 140 WOODCKFUSION" absolutely amazing price (particularly now) and good quality.
www.gong-galaxy.com/magazine/pics/1-hour-4-boards/If you're level is already nice and you a want a bigger challenge, the Naish Nalu Pro is a fantastic board.
The first collection boards were quite light but very fragile. I guess they might have improved. Look for feedback on the Seabreeze.
The Sunova Style would also be a great option.
The only downside of a 10 footer is the logistic aspect.
Have fun!