Here's why:
* Ir is an irregular verb in Spanish, meaning it doesn't follow the standard conjugation patterns.
* In the present tense, *ir* conjugates as follows:
* yo voy
* tú vas
* él/ella/usted va
* nosotros/nosotras vamos
* vosotros/vosotras vais
* ellos/ellas/ustedes van
So, the correct form for *yo* is voy.