I believe one kite and board is all you need to start and just learn to handle what mother nature throws at you, then when you have more knowledge and see and demo gear you will soon know what you want and what direction you want to head. For reference im 80kg 6'2 and started with a 12m Kite and a 138 board and with that setup ive been out in 15knotts to 30knotts(i was being pulled off my edge so i came in at that point)

But now i have an 8m which is wicked fun and a smaller board and a lot of other stuff.
When you first start it is more a matter of persevering with what you have and you do eventually get used to it. i would recommend a seat or board short harness until you learn proper kite control as it will increase time spent on the water and stop your ribs being sore for a week later.
Personal recommendation is also go new but superseded 2014 or 2013 gear if you can get it. (a lot cheaper and practaclly the same)