Because most of my friends believe that BTC reached 100,000 US dollars in December, so I want to discuss whether this is true

Those your friends believe that because they are holding some amount of Bitcoin and naturally every human is some how greedy and that was why they are expecting huge profit believing Bitcoin will hit $100k before December ending. I strongly believe that their expectations is unlikely because there is no sign in the current market trend of Bitcoin that it will hit such amount this year end.