Put in colour of my hair chestnut but don't like when can I redye it to a light brown

Dyeing hair can be tricky and very damaging. Going to a lighter color, even trickier because the chemicals you just used to dye it opened and damaged the cuticle of the hair making it more porous. And you cannot go from darker to lighter without lightening the hair first which involves more chemicals.
I would live with the chestnut for a while, better yet consult a hair stylist who is well versed in coloring.