google play upload APK fail, certificate invalid

hello I created a keystore already. and did everything right.... but now when i upload it on https://play.google.com/apps/publish/ it will say "Upload failed, You uploaded an APK signed with a certificate that is not yet valid. You need to sign your APK with a certificate that is currently valid. Learn more about signing."

can anyone help me?

by the way i created a keystore before but i deleted it since i forgot the password since it was just a trial run and created another one. i don't think that's a problem though right?