アメリカに行くことが小さい頃からの夢でしたって英語でなんて言うの？

All three of these sentences can be used interchangeably to have the same meaning of dreaming to go to America when you were young. The main difference between them is the structure of the sentence. As you can see within the first example, you can use the verb, "to dream," to describe this desire, whereas in the second and third you are referring to, "my dream," in the noun form. In addition, to describe that this was something you wanted/dreamed of when younger can be described as, "when I was young," or by saying, "when I was little."

There are lot of different ways of phrasing this. All of these phrases convey the key information: that you have wanted to visit America from a young age.
You could also say: I have always dreamed of going to/visiting America.

I have wanted to go to America since I was a kid and I finally went.
I finally went to America after wanting it for such a long time.
My childhood dreams have come true, and I got to go to America.

If you want to let someone know that you childhood dreams of going to a certain country has come true, then you can use one of these sentences to help you get your message across.

I hope it helps.
Have a great day.
Will

1) It was my dream to go to America ever since I was little.
「小さな時からアメリカに行くのが夢だった。」
ever since で「〜以来」
＊もしこれをアメリカで言っているなら、 It was my dream to come to America ... 「アメリカに来るのが夢だった」となります。

2) Now my dream has been fulfilled.
「ようやく私の夢が叶った。」
fulfill で「叶う」
come true を使っても良いです。

ご参考になれば幸いです！

You'd like to explain that going to America had been your dream since you were little, and you were able to realize that dream. The above examples may suit any situation like this.

If you have always wanted to go to America since you were a little kid, you can express this by saying something like "i have always dreamt of going to America ever since I was a little kid." or "Going to America has always been a dream of mine ever since I was a child.".

1. I can finally scratch a visit to America off my bucket list.
   If something is on your bucket list then it is part of your wish list.
   It is a personal goal that you want to achieve. If you can scratch it off
   your bucket list, then it means that your dream finally became a reality.
   Another example: I can finally scratch a holiday in the Maldives
   off my bucket list.

2. My childhood dream of visiting America has finally come
   to fruition.
   The phrase, "has finally come to fruition"means that your
   dream finally came true. In this instance it means that your
   dream to visit America eventually came true.
   Another example: Her dream to win an Olympic gold medal came to
   fruition when she won first place in the Ladies 100m sprint race.