Is "going" omitted between "am" and "there"? Or is this sentence grammatically okay?
There's nothing wrong with this sentence. "I'm there/I am there" is an informal expression used to mean "I'll go/I'm going" or "count me in." Joey has used it here to show his willingness to attend the event. Ex: A: Do you wanna get brunch on Saturday? B: I'm there! Ex: A: Did you hear about the concert next weekend? B: I'm there!
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