Why do very young couples often "fly in", and couples who want to have children often have problems with conception?

Dear friends, thank you for your answers! But speaking about older couples, I mean people of normal reproductive age, young families (conditionally 25-30 years old). Often, such couples need weeks or months for a positive result (all this, coupled with preparation for a conscious pregnancy), and very young (conditionally 16-20 years old) sometimes just one accidental unprotected (or insufficiently protected, for example, artificially interrupted) contact. I apologize for an inaccurate question or a wrong line of thought!

Because couples have less chance of getting pregnant with age. After 35, the chance of getting pregnant decreases to 5%, and the risk of miscarriage and successful childbearing also increases

I agree with Nastya on the 3rd point. Airplane marriage and childlessness are a sore subject for us. Because they talk about these problems.

So you hear about them much more often in relation to other cases.

Well, usually those who decide to have children late in the day have problems.
Now it's generally fashionable to get married and get married at 35 years old.
I think it's not hard to guess that health with our ecology and terrible rhythm of life - not at all.
Hence the problems.
And young people fly in because they neglect basic contraception.

Because, firstly, the young organism is more prone to conception, the sperm are fast, the bodies are not yet burdened with chronic diseases.

Secondly, the young are often frivolous or simply do not know how to protect themselves and as a result they do it as necessary

And thirdly, they just pay a lot of attention. In fact, I don’t think that the percentage of adolescents who have “flown” sexually active is very different from the percentage of the adult population with the same method of contraception