Age: 18-24 months

Q: When should my child have a dominant hand?

Answer: Most children have a preference for using one hand or the other by the age of about 18 months, and you will notice them begin to favour this more dominant hand. This could still change and children are definitely right or left-handed by the age of 3.

Source: https://www.verywellfamily.com/hand-dominance-what-is-a-dominant-hand-620856#:~:text=Infants%20develop%20unilateral%20manipulation%20skills,to%202%20years%20of%20age.