How did Jesus celebrate the New Moon feasts?

The NT does not say, though it's obvious that He would have observed rosh chodesh, since He came "in the fullness of time" (Gal. 4:4) to fulfill the prophecies to the exact moment of time (e.g., His crucifixion, death, and resurrection occurred in fulfillment of the "types" foreshadowed in the Torah). In other words, the LORD who created the "lights in the expanse of the heavens to separate the day from the night, to be for signs and for seasons, and for days and years" (Gen. 1:14) certainly would not have disregarded the signs He established regarding the coming of the Son of Man.