Yes. Your dependent will be required to file a 2018 tax return after making an IRA contribution of $3,000. It is the gross income that determines his/her filing requirement and not the adjusted gross income (after her retirement contribution). Taking the retirement contribution deduction will lower her taxable income and she will owe no tax due with that amount of income.
Please keep in mind that the self-employed filing requirements are different than the general filing requirements. If your dependent is self-employed during 2018 then he/she will be required to file a tax return if the earnings after expenses are $400 or more.
Click the link below to view IRS Publication 929 for more information about this rule.
https://www.irs.gov/pub/irs-pdf/p929.pdf
[Edited 04.09.2018 I 3:49 PM]
