There are a myriad of synonyms that can be used to express excitement over something. For instance, the phrase "become excited over" might be replaced with words like enthusiastic, thrilled, thrilled to pieces, stoked, exhilarated, overjoyed, ecstatic, animated, or thrilled beyond words. Other words that might be used to describe this kind of excitement include buzzing, jazzed, amped up, rearing to go, and thrilled to bits. Ultimately, the exact synonym that one chooses to use will depend on the context in which it is being used, as well as the desired level of intensity and emphasis.