My experience may be a little unusual when answering this question. I
had been dancing for 18 years before taking a Prelim. and had been teaching
SCD for 13 of those years.
I must admit that the years of experience certainly paid off, and if
some of you "eager beavers" could wait a bit longer than the suggested four
years, I think that you would find both the Prelim. and ultimately the
Teacher's exam. somewhat less stressful.