I don’t make (a lot of) money; do I still need to report to the USA?

Yes. Even if you have no earnings, it does not always dismiss you from filing taxes in the US; it will most likely result in you not paying any tax.

Basically, you have to file an IRS Form 1040 for the previous year if your income was above a certain threshold. These thresholds are the same as for US residents.  For tax year 2018 (filing in 2019) the thresholds (total yearly income) are:

Status Under 65 65 or older
You are single (unmarried) $12,000 $13,600
You are married filing jointly $25,300 $26,600
You are married filing separately $12,000 $12,000
You are filing as “Head of household” $18,000 $19,600
You are a widow or widower with dependent child $24,000 $25,300

Important note: Certain government subsidies such as child benefits, unemployment benefits, and subsidies are regarded by the US as reportable income that might make you reach the filing threshold.