When does a woman start to worry about her "clock ticking"?

I'm assuming you realize it's impossible to really answer this question, as it is such an individual experience. And for the record, not all women worry about their "clock." But in general, I would say it can start around 24 and get louder and louder, reaching it's peak around 30-35. By 40, if there's no conrete baby-making plans, I'd say a woman would probably start to give up on the idea of childbirth.

I know many women who decided to have children between the ages of 40-45. I have no opinion on whether this is good or not. One woman had a Down Syndrome child; but another friend in her 30's also had a special child. And 3 women I know had normal children.

That's 3 women over 40.

who is suggesting that you worry?

I think women start to worry around 30, but in actuality fertility starts to drop around 25 or so and all sorts of risks begin to go up. That doesn't mean a lot of women do fine much older than this, but biologically speaking, younger is easier and safer and healthier.

Here's the rule gals:

Early in, late out.
Late in early out.

That's to say if your period began at 11, you might be fertile into your fifties.
If your period began when you were 15 or 16, you'll probably start menopause before 40.

u worry wen u get gray hairs and get old lol