EFA/NCAS level 1

Im thinking about starting the level 1 instructors course. Im almost in yr 12 and have no idea what I want to do when I leave school, so im thinking this could be sort of a back up if something doesnt work out. It could also be used as income if im studying at uni or whatever.
I know im not the best rider and I will need to improve heaps. I know you can't sit for the exam untill your 18 yrs, but I have heard you can start it at 16? Im almost 17 by the way.
What are the current requirements to do the level 1?
I have an old book here from 1995 (was my mums lol) that says you need to:
- gain over 50% in a novice level dressage test
-be capable of riding a SJ course of 6-8 fences, max height 90cm
-XC course of 6-8 fences, 75 cm, undulating terrain

Are these still the same today?
I have heard its expensive, does anyone know how much it is?
I don't know, should I start it now or wait until I am older and more experienced?
Any info is greatly appreciated, thanks. :)