So I am trying to find this Korean drama I watched on YouTube. It was early 2000's and it's about a fourteen-year-old competitive swimmer and found a necklace and during an eclipse or something turned him into an adult. He befriended an older lady who was the owner of the necklace. I remember he was engaged to a girl who was slightly older than him and she refused although he was in love with her, I think she was in an idol group, anyways after he turned older the supposed fiancé liked him. Honestly it was a rather confusing drama because I watched it on YouTube but I still want to rewatch it so can anyone tell me if they know about this kdrama? If they do please tell me the title.

No he was like 14 and he didn't get married

He didn't go back in time or anything he magically turned older and had to live with his coach cause he didn't know how to explain his transformation to his family and after a while they thought he was kidnapped.

Pretty sure it was early 2000's because the picture quality was crappy but I cant be too sure

Depending on how motivated you are, you could check DramaWiki. It lists K Dramas by Year, you might see a name or synopsis that helps

https://wiki.d-addicts.com/Category:KDrama

If I have time one of these days I probably will

It is "I Love Lee Tae-ri" but you probably already found it haha

Holy crap that's it. OMG thank you so much!!!!