about " excited about" "excited by" and " excited at".
there are 3 sentences which are
1. I was very excited at the prospect of going to Europe.
2. I was very excited about becoming an uncle.
3. We're all excited by the prospect of a party.
I'm wondering the rule of using "by","at""about" naturally and correctly.
by the way, as you see the 1 and 3 have the very similar form, does they mean some differences by using "at" or "by".
thank a lot for your opinion

Question

about " excited about" "excited by" and " excited at".
there are 3 sentences which are
1. I was very excited at the prospect of going to Europe.
2. I was very excited about becoming an uncle.
3. We're all excited by the prospect of a party.
I'm wondering the rule of using "by","at""about" naturally and correctly. 
by the way, as you see the 1 and 3 have the very similar form, does they mean some differences by using "at" or "by". 
thank a lot for your opinion

Answer

I don't know the rules about this use very well. However I can say that in the US "at" is used much more commonly then "by". Really they all sound natural and correct.

Although "about" can mean "almost" as well. It doesn't in your sentence. It would mean "almost" in the sentence "I am about to be ready".

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