Do women really have to worry about “biological clock” ?

there is a good chance that I will be single until I am 40. If I don’t have a husband by the time I’m 35, I can always have a few kids of my own. Create a family of my own. I don’t get why people are constantly talking about “biological clock”. Women are designed to give birth and we can always have kids if we want them. Why worry about infertility at 45, if you are still fertile at 35?
Do women really have to worry about “biological clock” ?
Post Opinion