Nesting is sort of a myth. You don't just "start" because of something biological. Nesting is much more society based than anything else. Youre having a baby, so the natural need to prepare for that is common sense. Not everyone "nests". And not everyone "nests" by cleaning and making their house cute. Lol.
I do this to I have been cleaning for a few weeks now every thing is spotless and yet in my eyes its not clean enough I go to my sons room and fill like there should be more to do but all I can do is walk out good luck with the nesting
Usually 48 hours before labour. You might just have an energy boost.