Just do it! If it doesn't work then stop welding. A momentary arc flash is not going to hurt your eyes.
It's funny, I have a self darkening helmet, but mostly prefer my good old fashioned flip down helmet. Though the self darkening is great for tight areas.
If you're really that jittery, maybe consider using a standard helmet until you are more comfortable welding in general. And you will
get flashed on occasion. Just goes with the territory...especially when just learning.
Have fun and good luck!