Careful to Picky

Momon said I shouldn't be in rush to rush to get married.
Well, she obviously doesn't. Good for her?

When did it change from careful to picky?

Ouwh..I'm facing a Sorites Paradox

"1,000,000 grains of sand is a heap of sand. (Premise 1)
A heap of sand minus one grain is still a heap. (Premise 2)

Repeated applications of Premise 2 (each time starting with one less number of grains), eventually there's only one grains left.

Is it still a heap when only one grain remains? If not, when did it change from a heap to a non-heap?

Is it still called careful when you reject 150 proposal? If not, when did it change from careful to picky?