(Image credit: Getty Images) Nearly 40% of self-employed workers are baby boomers, according to a 2024 survey by Guidant Financial, and the number of older entrepreneurs has increased significantly in the past 25 years. Working for yourself in retirement, either full or part-time, makes a lot of sense: You can supplement your savings, stay engaged in your profession or try something new. But if you're new to self-employment , you may not be prepared for the tax consequences of going solo. In addition to income taxes, you'll also be responsible for paying the employee and employer portions of your Social Security and Medicare tax , which totals 15.3% of 92.35% of your net earnings. This often comes as a surprise to individuals who have spent their careers working for someone else, because employees who receive a W-2 only pay half of the payroll tax. Their employer picks up the rest. And since the employees' portion is usually withheld from paychecks, it may go unnoticed.…