The window is not an age range exactly, but a window of time determined by: 1. The current age of your child 2. How much less socialization they're getting tha

The window is not an age range exactly, but a window of time determined by: 1. The current age of your child 2. How much less socialization they're getting than their peers 3. Their natural proclivities towards socialization Socialization starts becoming important around ages 2-3. Points 2 and 3 being equal, the size of window expands as children age. Isolating your child about 6 months between 3.5 and 4 could cause a potentially permanent setback if not actively addressed. By age 12 a year of isolation is probably around the limit before rapid action is necessary. A major caveat to these guidelines is they don't really apply during COVID. While the reduced socialization for children is probably not good for them, lots of children are being under socialized and so your child can likely still find peers at similar socialization levels to interact with and not fall into the feedback cycle.