i hope the writer proves my theory wrong y’all!!!

Just dropping my theory here to see later if it's correct or not https://mydramalist.com/695149-twenty-five-twenty-one#comment-9155793

- 2521 is the age when their life changes. Maybe Heedo quit fencing, retire as an athlete, and shift focus to woodworking. And maybe Yijin hop on to a new career.
- The medals in Heedo's room that Minchae see (Ep1) are Yurim's because I think they're similar to what is seen in Yurim's room (Ep3) when Yurim chat as Injeolmi. Maybe Yurim handover it to Heedo when she leave Korea.
- Baekdo end game since Minchae is rooting for their relationship when she reads the diary.
- Still can't resolve the issues about the Kim name, Minchae asking who is Yijin to grandma, and adult Heedo can't remember the beach trip tho.

 Chanbrendoo:

Maybe Min Chae is Ko YuRim's daughter and Heedo adopted her because something happened to YuRim? I just don't want YiJin to be death 

This could very well be possible. An old story arch which common in dramas. 

Also I think I can now answer my own question about how MC can't recognise YJ. It's possible actually cuz she didn't know much about her mother too and as well the faces of her other friends.

Maybe she isn't interested in her parents' lives and feels pressure of having popular parents.

So I think it's possible that BYJ changed his surname and that's how MC is Kim not Baek.

I don't think Kim Min Chae is adopted because she wants to be the best at what she does - it's her grandmother's trait who bets on winning, she loves ballet and likes to win - it's a Hee Do trait, passion and dedication, but also the satisfaction of winning and finally also the fact that, at the same time as her young age, she was able to understand at the same time her mother's feelings from the past, but also she was able to assess and understand the situation of her grandmother - here is the event related to winning the first gold medal. For me, it is a reflection of the character traits of Yi Jin who could understand the Hee Do and Yu Rim when they were not yet friends. He did not directly support either side, but tried to understand them.

welp.. it was nice knowing u all

Watching the ending for episode 14, I realized that I've rarely, ever enjoyed a drama that blends past and present, but this one is flawless in storytelling and flow. There are times that words are useless and the eyes convey the real message. When Baek Yi Jin said, "congratulations on your wedding", his eyes said, "I miss you, I'm hurting". When Na Hee Do said, "thank you", her eyes said, "I'm resigned, there was no other option". Both still missing each other, both still in love with one another and I don't think I've ever watched a scene this sad.  As for the reason they are apart, I'm guessing something tragic occurs with Go Yu Rim and that issues ties in with Na Hee Do's marriage.  Truly, just a guess.

My goodness, my heart was broken into million pieces!!! I really hate not happy ending!!!!

 Kim MC:

Watching the ending for episode 14, I realized that I've rarely, ever enjoyed a drama that blends past and present, but this one is flawless in storytelling and flow. There are times that words are useless and the eyes convey the real message. When Baek Yi Jin said, "congratulations on your wedding", his eyes said, "I miss you, I'm hurting". When Na Hee Do said, "thank you", her eyes said, "I'm resigned, there was no other option". Both still missing each other, both still in love with one another and I don't think I've ever watched a scene this sad.  As for the reason they are apart, I'm guessing something tragic occurs with Go Yu Rim and that issues ties in with Na Hee Do's marriage.  Truly, just a guess.

F**k  so there's no happy ending 😔

still hoping for a good twist though…. but the words from Yi jin, congratulating hee do on her wedding, seems to be the big hint that they are not ending up together… 


such a cruel thing to end a rom-com… 

 Sam Arora:

F**k  so there's no happy ending ?

Your words are too the point and convey the thoughts of what most people feel. To me,  this isn't so much a rom-com but more of a coming of age storyline.  I'm hoping these two people find each but the magic of the narrative keeps me guessing.  I'm at odds trying to figure out the end.

 Kim MC:

Your words are too the point and convey the thoughts of what most people feel. To me,  this isn't so much a rom-com but more of a coming of age storyline.  I'm hoping these two people find each but the magic of the narrative keeps me guessing.  I'm at odds trying to figure out the end.

Idk I had a gut feeling that this won't realistically have that "ideal" K-drama ending with Happily Ever After and that's why I was reluctant to start this cuz although I don't have a problem with sad ending I just need proper closure but I wasn't in mood to watch something heartbreaking and tearjerking which I anyway ended up doing. This may have that "On Your Wedding Day" type ending you'd know if you've watched it. There were enough hints that ending won't be the one what most of us were hoping for and even went as far as thinking about different theories. 

I still low-key wish if I am wrong and the writers actually surprise us by showing that they were actually congratulating each other for their own wedding rather than HD marrying someone else but that have meagre chances cuz I always had this question that how come MC doesn't know about her father at all not knowing how they looked like when they were young is acceptable but how come she doesn't even know his First Name?

Well I used to 1/2 think that HD and YJ were endgame just because the drama gave so many like cues that they were not, like MC not recognising neither YJ name nor his photo, HD in the future forgetting about the summer trip, Grandma telling she met YJ and stuff.  Again the congratulations gave me the vibe that YJ and HD are married but are laying low from the public and haven't seen each other in months because of their schedules and hence the nearly crying faces. Or maybe MC might be JW and YR child and because they wanted her to be a Korean national dropped her off at HD and HD and YJ may have split. We have no news about YJ's fam in the last few ep so I'm also confused on that front. The title also really confuses me because YJ and HD are not 25 and 21 in the latest eps. I just really hope no one dies. 

I am about to stop watching this series.. Just don’t get it, it is quite unnecessary to give it a sad ending. What a 

waste, starting it with a cute and happy note, and ending it with reality check drama… just really stupid…

guys, there is the briefest of smiles on yijin's lips when he congratulates heedo on her wedding, maybe there's hope??