[masa]

I add or delete a comma like this, according to GRACE's suggestion.
(line3) You were smiling just at the moment we could meet, weren't you?
(line7) Because we started to walk and we don't need a reason for that
(line13) And we started to walk, hand in hand, still in an unfamiliar way
And I'm now thinking that "still in a kind of unfamiliar way" might be better.

As for the first and second lines, I think Mitkki's suggestion is good again.
Within your heart, you've actually been crying for a while haven't you?
But you were hiding it, that part of you hasn't changed.

As for the line 14, I add "certainly" (because I forgot to translate "tashika ni" into English), and change "just" to "simply" like this.
Because we certainly know at least that we are simply OK, we are OK now
But if it still sounds odd to you, please post your opinion here.

(line 5) Itsu datte wakatte ta ne wasureta hi wa nakatta yo ne
I still think that this line consists of two different senteneces (lacking of objects), and that it's very hard to interprete that [wasureta hi wa nakatta yo ne] is the object of [wakatte ta ne].