idk why people are mad at the ending for me it was the right thing to do she broke up with SML bc of his reaction but then she realized he's not a bad guy after dating ML she came to the conclusion to choose SML. I'm totally fine with the ending actually I saw it coming too I'm not surprised.
I have nothing to watch atm, do I need to start season 1 before this, or can I just ride the wave?
yes you should I also did I'm glad I did it. they do show flashbacks a lil bit so you won't regret not watching s1 and you'll see the development in yumi's character too. as you said you have nothing to watch atm then you should definitely watch s1