Roth, an unlicensed plastering contractor, performed work on a residence in 1988 but didn't obtain his license until after the work was completed. He filed a mechanic's lien but the court ruled against him. The New Mexico Supreme Court held that a contractor must be properly licensed at the time work is performed to file a valid mechanic's lien. This means unlicensed work—even if you get licensed later—cannot be protected by a lien.
Get your license BEFORE starting any work. The law requires you to be licensed when you perform the work, not when you file the lien.