How can I double check that I included my minor son's income in my 2019 tax return?

My son, then 16, worked a summer job and got a W-2 for wages earned ($1,477.50). Taxes were withheld. I'm filling out a CSS financial aid application for college and it is asking if my son filed a tax return. I answered, "No," and they want him to sign a form saying he wasn't required to pay taxes. Now I'm worried that I made an error. I'm pretty sure I included his income in our married/filing jointly return but I don't know how to verify that. I don't see the amount he earned on any line in my tax return. I'm wondering what to do.