Do I need to report my income of less than $100 when I'm 14 years old?

No. You do not need to file a return.

A dependent must file a tax return for 2017 if he had any of the following:

1.         Total income (wages, salaries, taxable scholarship etc.) of more than $6,350 (2017).

2.         Unearned income (interest, dividends, capital gains) of more than $1050 (2017).

3.         Unearned income over $350 and gross income of more than $1050

4.         Household employee income (e.g. baby sitting, lawn mowing) over $2000 ($6350 if under age 18)

5.         Other self employment income over $400, including box 7 of a 1099-MISC

Even if he had less, he is allowed to file if he needs to get back income tax withholding. He cannot get back social security or Medicare tax withholding.

 He doesn’t get his own $4050 exemption (deduction), when he files. In TurboTax, he indicates that somebody else can claim him as a dependent, at the personal information section.