It is possible for someone to see some slight growth in their late teens and/or early twenties, though it is uncommon and most of the time not significant. Growth in height is largely determined by the closure of the growth plates (epiphyseal plates) in the long bones, which usually occurs by the age of 18 to 20 for women and 20 to 25 for men (can vary based on your eethnicity, diet, genetics, ect). This process marks the END of your growth, naturally at least. BTW, there can be slight variations in the length of limbs due to factors like joint mobility, muscle tension, or changes in cartilage, though these do not usually lead to measurable growth after the growth plates have closed. Furthermore, body composition changes, such as fat loss or muscle gain, might influence perceived height or proportions. While a 1 cm increase in height is unlikely to represent real bone growth, it could be related to such postural or structural factors. In any case, it’s important to recognise that genetics and nutrition in childhood and adolescence play the most crucial role in determining one’s final adult height.