"I finished my studies with the best result, a big A." -> I don't think this is natural English...
I would rather say: "I passed my studies with the highest grade, with an A." -> Is this sentence more appropriate?
Thanks in advance to anybody ;-) Claudia
The "dispassionate" way is to say "I got an A', but the speaker may want to show their delight and add an adjective.
One student might say: "I got a big fat A". However, they would never use that expression in any official context such as a letter applying for a place at college or a job.
Be careful with expressions like "highest grade" - an A might not be the highest grade; it depends on which examination we are talking about.
For example, some British exams have an A* ( that's read as A star).