"Consider" with the meaning of "contemplate" can be used in two ways: 1. consider doing something (i.e. consider + -ing verb): EX. She considered resigning. 2. consider + wh-word + to-infinitive: EX. She considered where to hide the money.
So the sentence is incorrect, because "consider" cannot be followed by a to-infinitive. It should be "She is considering not going."