In California, you need to be 18 years old in order to both own and be able to sell or make contracts relating to real property.
However, under California law, a minor (under the age of 18) may own real property or an interest therein (Estate of Yano (1922) 188 Cal. 645, 649), but a minor may not convey or make contracts relating to real property. (Family Code, § 6701, subd. (b).)
Therefore, a minor cannot sell or purchase property held directly in his or her own name, and, as a practical matter, transactions involving minor’s interests in real property are usually conducted indirectly, through a guardianship or trust.
The California Uniform Transfers to Minors Act (Prob. Code § 3900 et seq.) (CUTMA) provides a statutory mechanism for transferring property to an adult “custodian” for the benefit of a minor.