Hi Eirrab,
I have around 3 years of experience on SUPs.
At your height and weight I would go for a 12'6" board, something like the Fanatic Strike, Naish Javelin or Starboard Race. The width of the board dictates how stable it will be, and stability is important just starting out. Go for around 27" I think any wider with you may make it hard to keep the paddle blades away from the sides of the board.
I used yo fly Hang Gliders too
Good luck,
Ed