We were recently talking about how it's almost December, but now it's almost the end of the year! It all goes by so quick.
ご質問ありがとうございます。
↑で書かれた文章で完璧です！
一応、他にも使える文章を書いておきました。
"We were recently talking about how it's almost December"＝「最近、もうすぐ12月だと私たちは話していた」
"but now it's almost the end of the year!"＝「でも、今はもうすぐ年末だね！」
"It all goes by so quick."＝「全てが早く去っていくね。」
ご参考に！
アメリカ合衆国 
