It is innate, in that the ability to perform magic is not something every living person possesses, in my world. My parents, for example - wholly non-magical. I was the first witch of our family, actually. But there are people who come from old magical families, who have always been around magic - grown up in magic communities, were around it from a young age...

So, innate to som people, but the skill part is very much learnt. When we turn eleven, all magical children are expected to attend some form of formal education, it's where we learn how to cast our spells and brew our potions.