Made a mistake on Common App, not sure what to do

I submitted my app to my schools yesterday–I thought I had proofread pretty thoroughly, because I did catch and fix two errors, but today while I was rereading I realized I made a mistake with reporting my class rank. We won’t receive our official number rankings unless we’re in the top ten of the class, which I’m not, but I had used the number I was given last year (20 out of 387) as a placeholder while I was originally filling out the application. Our class size has been amended to 406 since then, and I don’t actually know my official number (though it’s almost definitely not lower than what I submitted), but I put 20/387 on the common app. I don’t know what I should do, or if this’ll ruin my application…if my school report has the actual class size, which is different from the one on my app, will they think I lied and made the number up? Should I email the admissions offices?