Could you please confirm or provide a better translation for this?
Do you have to act so surprised that I've finally made it?


You have finally become successful. You tell someone. This person is surprised.

Within the context, I don't think Chinese would need the last part 'that I've finally made it'

你有必要表现得这么惊讶吗？
Do you have to act so surprised?

But if you really want the last part, try putting it first:

我最终的成功真的让你这么惊讶吗？
That I've finally made it really surprises you that much?

Edit: with the vpn on, I could see your picture.

你们俩看到我这个体育渣自己跑上来吓傻了。
You two, seeing me, a physical wreck, run up here on my own, I bet that scared you silly!