兴奋 means "excited"/"stimulated" and generally in a positive way. So if you are looking forward to something, 兴奋describes that state of mind more closely. Examples: 消息传来，人人为之兴奋。As the news arrived, people got really excited. 这是一个令人兴奋的场合。This is a very exciting occasion. 我们都为这消息感到兴奋。We were all excited by the news. 麝香被用作香料和兴奋剂。Musk is used as a fragrance and a stimulant (this shows how 兴奋 is closely related to "excite," "stimulate"). On the other hand, 激动 is closer to "emotional." Examples: 他一辩论起来就十分激动。He gets very emotional when he starts arguing. 潘是个非常容易激动的人。Pan is the type of person who easily gets emotional. 我容易激动，却不爱报复。I get emotional easily, but I do not like to seek revenge. 这段旧梦重温使我很激动。This rekindled old dream made me very emotional. Hope this helped!

兴奋多用于表达高兴遇到开心的事情， 激动既可以表达高兴同时有时候愤怒也会变得激动。如果你想表达开心的期待某件事情的时候用兴奋就可以，这样会比较准确，

興奮 has tones of being exhilarated. It only means happy/positive moods. 激動 means more fluctuations in mood, or a somewhat extreme one. It can be both positive and negative. Baidu says this https://zhidao.baidu.com/question/201340206913276125.html

查下词典就好了，两个意思的差别很明显的。如果说想用来表达”开心“的期待，严格的说都不是，因为”兴奋、激动“都不是开心的意思。如果用来表达”期待“都可以，程度上应该很难比较。因为它们表达的是两种状态。