Перевод - Японский-Английский - うれしい！たのしい！大好き！

Original version of translation, before edits:
---
I'm happy ! It's great ! I love it !

私はこの歌を知っていますが、歌詞の内容を考えると
"I'm happy ! It's great ! I love it !"
は違うと思います。カテゴリが”歌”ということを鑑みても単純に"it"と訳すことは間違いでしょう。もし歌詞の内容を踏まえて訳すならば、"I'm so happy, it's really fun(when I'm with you), I love you"　が妥当と考えます。まあ、ただの言葉として訳したのでしょうからあなたの翻訳は間違ってはいませんが。ただ日本語はもう少し複雑なものですよ。。

English translation of lily w's comments written in Japanese above:

---(translation starts)---

I know this song, and taking into consideration the meanings of the rest of the lyrics, in my opinion, to translate it as
"I'm happy! It's great! I love it!"
does not reflect the intention of the original Japanese.
Even taking into consideration that it is in the "song" category, I think we cannot simply translate the last phrase as "I love it." In the context of the rest of the lyrics of this song, I believe it would be more suitable to translate this text as
"I'm so happy, it's really fun (when I'm with you), I love you."
Of course, because the translation was done without the benefit of the context of the original Japanese, I suppose one can't say that the translation is literally wrong as such...
It's just that Japanese isn't quite as simple and straightforward as most Western languages (i.e. it isn't as context-independent).

---(translation ends)---

For what it's worth...

先の私のメッセージのポイントは”歌詞の内容を考えると”、”もし歌詞の内容を踏まえて訳すならば”にあります。（お分かりいただいていると思います。）
直訳であれば"it"でいいのでしょう。投稿者はこのフレーズを歌詞の一部として投稿しているので、この歌詞の意味に当てはまらない可能性があるという説明を付け加えても良かったのではないでしょうか？ただの直訳ならばgoogle translateでも変わりませんからね。
私が言いたかったこと分かってもらえました？

Translation of above:
---(translation starts)---
The important point I wanted to emphasize in my previous message was "Taking into consideration the content of the (rest of) the lyrics," i.e. "If we translate this in the context of the rest of the lyrics." (I think you understood that.)
Literally translated out of context, "I love it" is also correct. Because the requester put his request (in the "Song" category) as part of a song, maybe when the translation was done, it might have been a good idea to have attached a note to it, saying that "It is possible that this translation might not exactly reflect the meaning of the original, in its context of the other lyrics of the song." To simply translate something literally, one could always just use Google translation, you know what I mean?
---(translation ends)---

Thank you for your input, Lily! I indeed agree with you that translation is always best done in context, and where there are several alternative translations due to a lack of context, that we should include the other possibilities as well, in the notes below the translation.

I look forward to checking your translations in the future! Please click here to see some translations which are waiting to be done!

Sorry, I also agree totally with your point of you Lily. And I'm really thankful that you helped us with that translation ! I didn't know it was part of a song and indeed, without knowing the context, I translated in a wrong way. I'm going to change my translation as soon as I find out how to do it, because I'm new on this site

Hi ennynla,
Actually, now that the translation has been validated (by me), the translator (i.e. you) can't change it anymore, but an English expert (i.e. me) still can, so I'll do that for you right now!
Thanks again for your interest in translating!

Thanks guys. I was just trying this translate better. And ennynla, yah I was guessing you don't know the song.. Anyway, we can learn new words, new things each other on this site, maybe it's worthwhile to use our brain and take our time. I also newbie here. Let's improve & enjoy! And Ian, I appreciate your translate my msg jpn to eng. but I'm a sarcastic person more than you think. I should've wrote in eng, thanks and sorry for took your time.

No problem, Lily! It's my pleasure!
That's why I come here to !

And "sarcastic" is okay too! Everyone has their own personality: that's what makes the world wonderful!