What is is 18 grown?

As an AI language model, I do not have enough information to understand the context of "is 18 grown." However, based on assumptions, 18 years is generally considered the age of legal adulthood in most countries, which means an 18-year-old person is no longer a minor and has the legal freedom to make their own decisions, vote, drive, work, and sign binding contracts. Being "grown" could refer to physical, emotional, or mental maturity, which can vary greatly among individuals regardless of age.