Based on the title alone you can already guess that this drama is about a 30yr old woman who feels mentally 17, but the story is much more than that. Ignore the synopsis, which seems pretty cliché, and just be open to a well-told feel-good story. I love sentimental stories, but this one is particularly good. It's the kind of drama that reminds me to not get stuck on what has gone wrong in the past and instead be able to appreciate what can and will go right in the present/future. I won't give any of the plot away, but from the very first episode, I laughed and teared up and I still had no idea how much this drama would grow on me... a definite crescendo "<".

It stars Shin Hye Sun or Yang Se Jong and they really are a dream match. I find it funny that neither of them is actually 30, but I guess that makes sense since both characters are stuck in their pasts. Shin Hye Sun as Woo Seo Ri does an amazing job of handling all the emotions her character has to go through, and seeming inappropriately youthful without being too silly. I was also extremely impressed with Yang Se Jong as Gong Woo Jin who was both heartbreaking and heart melting in his role. They had a great chemistry which felt honest, and sweet, and I absolutely fell in love with them falling for each other.

The supporting cast is pretty much perfect. I loved Ahn Hyo Seop as the super cute jock Yoo Chan, and his bromantical and hilarious teammates. I really liked Woo Jin's coworkers, and how they dealt with his antics in a caring way. I was also extremely happy to see one of my favorite K-actresses Ye Ji Won as Jennifer, a kind of robotic Mary Poppins character who easily became one of my favorites in the cast. I may never be able to say "Jenni-fer" normally again! Even the dog was great!

I also have to mention how well all of the younger versions of the characters matched their older versions. They did not have to look like perfect matches to match their personalities perfectly. For once I wasn't annoyed by constant flashbacks, because every look back made sense and added to the depth of the story. I appreciated that.

Another unsung favorite in this drama is that house! I haven't fallen in love with a kdrama home like this since "Secret Garden".

So, does this drama really cover romance, comedy, drama, mystery, and music? Kinda, but not in a way that feels disconnected. I also love that all of the parts of the story seem well thought out and connected. Even what should seem improbable feels like it makes perfectly reasonable sense as more of the story is revealed.

Music is also a major part of this drama. Although the original songs were appropriate, they were not particularly memorable. I just liked the way love of music was shown throughout the story.

Would I watch this again? Definitely! Not only was it easy to binge through (32 episodes even felt short), but It'll be fun to rewatch it all knowing there will be new moments to catch now that I know the full story. I already caught something while rewatching the first episode that I definitely had no reason to notice the first time. A small trivial thing, but a huge part of the story, just like this drama's overall theme. I definitely want to applaud the writer for paying attention to those kinds of details.

There were a few minor parts of the story that felt a little rushed through as far as explanations, or became less important, but not in a way that affected the pace or telling of the story at all. I hear that it was originally much longer which is probably the reason. Still, I was more than satisfied with the end, which felt pretty perfect and solidified this dramas spot on my favorites list.

So if you're thinking about watching this drama for any reason, just heed the advice of Yoo Chan... "Don't think, feel!" or rather "Don't think, watch!" This drama definitely got me in the "Feels" and I loved every single episode of it!