Yes, a trainer kite is the best way to start.
It makes a lot of fun and you learn to steer and control the kite without being afraid of getting dragged or lifted.
Then you should attemp a school and get lessons.
IMO a kite of 9-12 sqm total size is good for starting in 3-4 Beaufort after you had lessons.
As to boards, the latest trend is to get a smaller twintip than a large directional.
180 cm is a good size. With a smaller TT you need more time to get going, but therefore you can skip the turns with changing feet. So you will be less in the water than on the water!
But do lessons and then you will be able to judge better for yourself, what is the best for you.
Welcome to the world of kitesurfing