Positive test but period next day

Okay so this has been on my mind for a while now. In June 2019 I got a positive pregnancy test the night my period was due because my boyfriend kept saying take a test he think I’m pregnant and I told him it was impossible because we wasn’t having sex my fertile window, the next morning I took another one and it was positive as well. They were the cheap 89c test from Walmart that I bought around December 2018. I got my period that same afternoon and I was honestly just like “I told you I wasn’t pregnant”. I’m now 4months pregnant with a healthy baby boy and when I have to fill out forms that say “is this your first pregnancy” that moment always replays in my head cause I don’t know what was the cause of getting those two positives in 2019. Maybe the test were expired? Idk