[Quick Explanation on Levels/Steps] - (SPOILERS)

Step 0 - Before magical maturity. Hardly any wizards experience this level as usually the core presents itself just before magical maturity rather than years before. Oz however found his core at 5 making him an anomaly, allowing him to self-harmingly train to his first maturity earlier than others.

Step 1 - Magical Maturity. The step most witches and wizards are in around the globe. If this were a medieval hierarchy this would be the "commoner" stage.

Step 2 - 2nd Maturity. This step is for the more adept witch and wizard. I usually refer to this level as the "Teachers and Aurors" level as thats who mostly occupy this level in the grand scheme of the story.

Step 3 - 3rd Maturity. A level only powerful wizards like Dumbledore, Grindelwald and Voldemort have achieved.

Step 4 - 4th Maturity. Only Legendary wizards reach this level. Salazar, Helga, Rowena and Godric probably all resided at this level of power along with other wizards of that time that left legends.

Step 5 - Final Maturity. ???