straight A

achieving or showing the highest grade or superior accomplishment, especially scholastically: a straight A report card.

Origin of straight A

First recorded in 1945–50

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Funke would have been remembered as a pretty freshman or a straight-A student by friends and probably forgotten by most.
A College Student’s Death Is Now a Talking Point About Porn|Emily Shire|May 23, 2014|DAILY BEAST
First reports detail the shooter as Sergei Gordeyev, a young man around 15 years old, and reported to be a straight-A student.
An American-Style School Shooting in Moscow|Andrew S. Bowen|February 4, 2014|DAILY BEAST
I think viewers assumed Daphne was a virgin because she was a ‘good girl’; a straight-A student, etc.
Television’s 20-Something Female Virgins: ‘Girls,’ ‘Grey’s,’ and ‘Underemployed’|Whitney Friedlander|November 27, 2012|DAILY BEAST
But being a straight-A student doesn't coincide with sexuality.
Television’s 20-Something Female Virgins: ‘Girls,’ ‘Grey’s,’ and ‘Underemployed’|Whitney Friedlander|November 27, 2012|DAILY BEAST

She looks very much like the straight-A student she indeed had always been.
Was Autumn Pasquale Killed Over a Bicycle? Teen Brothers Charged|Michael Daly|October 24, 2012|DAILY BEAST
Well, geeve-a me youse-a da hand and Eesa take-a you straight-a da heem.
An Oregon Girl|Alfred Ernest Rice