I'm so happy.

我太高兴了。

I'm overjoyed.

简直让我喜出望外。

I'm flying.

我有点飘飘然。

I'm delighted.

我很高兴。

I'm so happy, I can hardly contain myself.

我太高兴了，简直抑制不住自己的兴奋。

ecstatic

狂喜的；

They are ecstatic about their first kid.

他们为有了自己第一个孩子而感到欣喜。

dialogue1

A: I can't believe it, I'm so happy I got an A.

我简直不敢相信，我得了一个A.

B: Congratulations. Your father will be so proud.

恭喜。你爸爸一定为你感到骄傲。

dialogue2

A: What's up? I've never seen you look so happy.

怎么了？我从没看你这么开心。

B: Jennifer just told me she loves me, I can hardly contain my excitement.

珍妮弗刚刚说她爱我。我实在无法抑制自己的兴奋。

Conversation:

A: Check this out, I just got accepted to grad school.

快看看，我考上研究生了。

check this out非常地道，用来引起别人注意自己下面要说的话。

B: That's fantastic. What a great feeling that must be.

太好了，你肯定感觉棒极了。

A: That's for sure, I'm walking on air right now.

当然了，我现在都有点飘飘然了。

walk on air字面意思是“在天上走路”，形容人高兴地飘飘然

B: Well, you worked really hard, so you deserve it.

你学习那么努力，这是你应得的。

A: Thanks. When I show my dad, he's going to be ecstatic.

谢谢，我把这个消息告诉我爸爸，他肯定会欣喜若狂的。