Children over the age of 18 years old can be included, however, they must remain dependent for each year until citizenship is achieved. There is no official age limit for dependent children, but we would advise no older than around 22 or 23 years as they need to remain dependent for the five-to-six-year period following. In reality, it can be much harder to prove a 28 year old child is still dependent, unmarried and in full time education, although it is possible.