The early universe was almost perfectly uniform. Its oldest light — the cosmic microwave background — is smooth to about one part in a hundred thousand.
Almost. Those faint differences, tiny ripples of denser and thinner, were the seeds. Gravity pulled the denser spots together, and over billions of years they grew into everything: stars, galaxies, planets, you.
A perfectly uniform cosmos would have stayed a featureless fog forever — nothing to see, no one to see it. Structure exists because sameness broke. And the elements you are built from? Difference, forged inside stars.