I've been in ATC now for 44 years now, and, one way or another, helping to train aspiring young ATCO trainees for some time. I still don't know what makes an ATCO. If I did I would bottle it and make a fortune. I can sometimes tell quite early on in the training who will not/should not become an ATCO, but I have been wrong sometimes. I have a theory that those who have qualifications in the arts as opposed to the sciences are more likely to become good controllers, but that may be total hogwash. I also have theory that a higher percentage of ATC graduates are left-handed. Make of that what you will.
In short, the only predictor is the assessment process, the system cannot yet tell you your fortune.