I understand that the form says "net business profit". The IRS classifies self-employment income as business activity, even though a formal business has not been established. All income earned through cash payment for personal services that are not tips, and 1099 income with box 7 income, to be self-employment income requiring the filing of schedule C.
All such employment income, that escapes W-2 treatment, is subject to SS and MC taxes in the form of SE tax.
There is no state in the U.S. that requires a business license to be self-employed. However to be self-employed by profession may require a license. For example: one can not hold themselves out be an attorney without a license; one can not hold themselves out to be doctor, nurse, CPA, etc without a license. I know of no license one needs in your state to teach Spanish in that environment.
However, it does not matter if you have a license or not. Even if someone were illegally self employed by virtue of requiring a license for their profession, they are still required by federal law (I.R.C) to report all income even if it is illegal.
Remember the stories about Al Capone...they got him for not reporting his illegal profiteering income to taxes. He got caught for tax evasion.
A person can be a drug dealer, prostitute, hustler, gambler, or Spanish teacher, and they have to all report their self-employment income on schedule C and pay SS and MC taxes on schedule SE. (I can not judge if people really do report the taxes illegally gained).
You are not a business, it is self-employment and is considered business activity by the IRS.