See this Social Security website for self employment information - https://www.ssa.gov/pubs/EN-05-10022.pdf
As stated in the Social Security Statement -
Call us right away at 1-800-772-1213 (7 a.m.–7 p.m. your local time) if any earnings for years before last year are shown
incorrectly. Please have your W-2 or tax return for those years available.