Roth Ira contributions for 2020

So I'm kinda new to investing, I opened my first Roth IRA in June 2020. The confusion is that I filed my taxes early in March 2020. Then I found out after that the taxes and contribution due date were extended to July.  So in June, I contributed $3,081 for 2019 but I already filed my taxes so I'm not sure if I'm supposed to include it on my 2020 return or if I messed up and have to amend my 2019 returns?