If it’s just because they are embarrassing I would personally just learn to live past it and accept it. If this were a public place we all talked, we wouldn’t be able to take back the words we’ve said once we’ve said them. It’s good to learn from if you really can’t get anything else out of it. And I get it, I have perfectionist tendencies, so I hate how I’m represented to be anywhere out of place. But it’s just pointless overthinking. Don’t obsess over it and let your new posts show the differences.
Most people aren’t going to obsessively look through your history anyway. I mean, this does ironically increase the chances though... but I doubt it’ll be used against you ever. And if it is, you can be honest and say you regret those posts. That’s just part of growth.