Well I watched this drama with alot of expectations and it was holding on to that untill the last few episodes!
Pros:

The chemistry between the leads was refreshing and entertaining to watch despite the age gap!
The side character's story were good and their friendship also worked in favor for this drama.

Cons:

This is one of the few dramas where I would prefer sad ending over this called "happy ending" that we got.
I kept replaying the last episode to see if I missed any episodes inbetween because everything looked out of place and directionless.

Him returning back after years and FL being so calm and understanding baffled me.
It looked like writers were onto something at the start of the drama and guess what "IT WAS DISASTER."

The acting from both the leads just couldn't save the story!

I am trying not to sound rude but it gave me "11 year old wrote her first Wattpad story !" vibe. I would literally sign petition for Netflix to remove the last episode of this drama.

I would recommend this drama till episode 12 or 13 and then I would suggest to imagine a better ending ( I bet - If the multiverse exists, most of imagined endings would be better than what we got) and then drop the drama!