My parents don't like my boyfriend because of his first impression on them which was 6 years ago. What should I do ?

I would try and show your parents how he's changed and tell them that sometimes first impressions are awkward and that people make mistakes and that’s alright cause everyone is human I know that it might not entirely feel like the right thing trying to tell your parents something different about an opinion they already have on someone but sometimes first impression opinions are wrong just tell them politely and tell them that their opinions and concerns are heard and are being taken care of just because he did something six years ago doesn’t mean it should be held against him today.