Board Thread:Manga/@comment-44262252-20191102162341/@comment-30473998-20191104050118

The first season of the anime covers chapters 1-33 or 34, which is around volumes 1-8. If you insist on starting where you left off, I would suggest reading through volume 8 instead of skipping to volume 9, since the transiton between S1 and S2 happens within volume 8. However, like TKGriffiths said, you are missing out if you don't start the manga from the beginning. The "Humanity's Comeback" arc in the anime was only two episodes long and cut out a lot of content from the 104th Training Corps arc, which is its equivalent in the manga.