Need to file Extension 4868 for filer not REQUIRED to file a return at all?

[DontMindTaxesThatMuch]

Our college student dependent (over 18 years old), who has NEVER filed a tax return,  does not appear to be required to file a return this year either (her income appears to be lower than the amount required to file). But she may file anyway for 2024, to declare increased taxable income to allow parents to claim the American Opportunity Tax Credit.  

Since she's away at college and not ready to file by April 15th, we are wondering whether she must/should file an extension by April 15th. We don't think she'll owe any actual taxes, but if she does owe anything it will be a very small amount. 

Must/should she file an extension for this year by April 15?

Thanks!

[MinhT1]

If she does not owe any taxes, she's not required to file an extension.

Also she does need to have taxable income for her parents to claim the AOTC for her.