Oh God....Venial sin doesn’t separate us from God like MORTAL SIN does....really....who taught you these things??? EVRYONE had VENIAL SINS....we ARE venial.....but not everyone ever has a MORTAL sin.
Like .45 Long Colt said, Scripture does not distinguish between mortal and venial sins, that is a man-made distinction. However, Scripture does say “all have sinned and fall short of the glory of God” (Romans 3:23) and “the wages of sin is death” (Romans 6:23). All unforgiven sin leads to eternal death, therefore it could be thought of as “mortal”.