Hey there Chief, the most imporant is to make yourself look good so the best thing is to just make up an age that is helping you do that. Second method is from seed that means from the first moment you start the seed. Third method is to start from the day of the first transplant (from the propagator to the pot), and actually the last method is simple, just grow the seedling for a while, then after a couple weeks, when it's not really a seedling anymore then you start counting. That's what i've seen so far, i use the method counting from sprout. Hope this helps !
