Yes.

Actually liking yourself without pressure will make other people like you (and you won't try to win over the ones who don't).

The ones who don't like you? You won't resent them, you'll just accept that as a fact..

And no, you don't need proof of achievements before you start liking yourself.

You can like yourself completely right now, and you'll automatically start getting those proofs and achievements.

Slowly, your habits, thoughts, words and actions will start matching it.

Not slowly, it happens quite fast.