Yeah, you need a similar score to GPA of 3.7-3.8 at University to be successful at day trading.
Then there is a problem: I never went to university and am nevertheless (very) successful in trading.
Before I became fulltime trader I was treasury manager in a billion dollar company and a few of the people working under me had university degrees. But I got the job, not they. The company was not happy when I left to start trading fulltime.
One of my children, who has no university degree but a degree just below that in biochemicals, has a very high position at Johnson&Johnson (medical division), responsible for people all over the world. She reached this level when she was in her early 30's. When she started she was the only one in the department without a university degree. They took her because of other important qualifications (that had nothing to do with being female, so no vaginal promotion) .
I still meet people from my last job. They have university degrees in economics, one even has a doctors title. I help them with trading. None of them is, after several years, able to make any money. They even tried to work together as a group and share all their "knowledge". Even with a few valuable hints from me they still are nowhere.
Trading has nothing to do with a university degree. If you think that you made it because you have a university degree, you are wrong. Life will teach you that there is no one on one link between this degree and your salary.
In trading probabilities are important because they can help you making money. In deciding wether to become a trader or not, probabilties are useless. So don't care if 90% never make money. In every area where there are succes stories, the majority will never have succes. That's the "defintion" of succes: achieve something most cannot achieve. If not it would be called mediocre.