Final answer:
Patricia is most likely around 24 months old, as her behavior aligns with the developmental milestones typical for toddlers asserting their independence at this age.
Step-by-step explanation:
Patricia's increased use of the words "me" and "mine" and her selfishness with toys indicate that she is likely in a developmental phase where toddlers begin to assert their independence. This behavior is characteristic of a toddler at about 24 months old, as children in this age group are learning to navigate their sense of autonomy versus shame and doubt.
By two years of age, toddlers often show clear preferences for their environment, exhibiting behavior such as choosing their clothing or being possessive with toys, which aligns with Patricia's observed behavior. They may exhibit possessiveness over toys and use words like 'me' and 'mine' more frequently. Additionally, they may engage in frequent temper tantrums as a way to express their growing independence.