How do you write a 4-year and 8-months old girl?

To write about a 4-year and 8-month-old girl, you can express her age as "4 years and 8 months old." Alternatively, you could say she is "4 years old, nearly 5," to emphasize her age progression. Additionally, you might describe her developmental milestones, interests, and personality traits that are typical for her age group to provide a fuller picture.