Classic World of Warcraft: Shadowlands me being a new player?

I'm a new player at wow and I enjoy the game, but I don't know if I should buy Shadowlands or just stick with the subscription, One of the reasons for wanting to buy shadowlands would be to have a fixed story to follow, as I sometimes get confused because when I am doing a mission of a certain expansion and sometimes out of nowhere a cinematic/mission of another expansion appears. via /r/wow https://ift.tt/3rgoOFe