Subject to tweaking to fit into your world, I’m thinking, Cael, an orphaned kid. Parents could be alive or dead, known or unknown but not involved with the character so far. I can decide on those details myself, but I thought it might be a chance for you to make up some background mysteries that I don’t know about. Let me know if you’d rather I choose.
Grows up in some kind of institution/orphanage with an oppressive (but not necessarily abusive) staff. Cael was exceptionally intelligent and the orphanage provided (and forced) an above average education and developmental resources to allow Cael to reach his potential. This made Cael even more discontent with the lack of control of the direction of his life as he realized what was possible and dealt with the restrictions that kept him from those possibilities.
Cael’s struggle for control of his life was also complicated by the politics of the schoolyard. The staff of the orphanage was not big enough to keep constant watch over the children and so, they formed their own sub-society as always happens. Being orphans, it was a tough group and early on, Cael learned to keep a low profile and developed the stamina to hold his own in a fight when necessary, knowing that to back down was to become a punching bag for the rest of his stay. But holding his own didn’t gain Cael the control of his life that Cael needed. He was not charismatic enough to stand out as a leader, and there were plenty stronger to keep him from muscling his way to power. Fortunately, Cael was easily the smartest boy at the orphanage and was able to maneuver and manipulate his way to security by picking the right friends, the right enemies, and the right pawns.
The control gained this way made life more comfortable, but did not free him from the oppressive rule of the staff. To rebel, he would undermine rules and teachers whenever possible, rarely getting caught, framing others if necessary.
Cael also took advantage of the learning opportunities and resources available at the orphanage, absorbing as much as possible and studying and researching constantly at the library. During this research, he came upon a rudimentary text on magic. To most, this text was too conceptual and abstract to be of use and to practitioners, it was too trivial to bother with. Cael’s ability to learn and natural aptitude for magic (maybe from one inherited from one of his unknown parents, but who knows) allowed him, after years of study, to unlock magical energies and cast spells (maybe one or two cantrips) which he used as tools to get more control.
I won’t be too specific about the next part because I don’t know what the starting situation will be: Cael comes in contact with a wizard (maybe visiting an official at the orphanage) who recognizes his talent, catching him casting a cantrip. Seeing that he was able to achieve even 0-level magic with no formal training, the wizard puts Cael in an apprenticeship situation (him personally, placement at a school, etc).