You shouldn't worry about anything in life. No matter what it is. Everything's such a trifle!

in the singular, TRIFLE is an English dessert. When we mean мелочи, we use the plural TRIFLES.

We shouldn't worry about anything in life. No matter what happens. These are all peanuts.

PEANUTS is used in this way when it refers to little money: The car looks impressive, but it cost him peanuts. Here you need TRIFLES or TRIVIALITIES.

+++Jane: Very intuitive, inventive, creative and idiomatic RENDITION of the original post. Brava!

You shouldn't worry about anything in life. No matter what it is. Everything's such trifles!

Here you could say: It's all trifles.

Jane, I was referring to this one: It's never worth regretting anything in life. Whatever it is. It's all so insignificant! - Excellent!

Uly, thank you so much for your corrections and kind words! Прямо бальзам на душу)))

My pleasure 😇