You have to be in the council of a coven to be able to cast spells. I see you are in Spell Casters though, so you can already do that.
You are free to add and write spells if you desire, but I have noticed from your past posts that you don't really know what you are doing. You are very new, so I would study what magic really is before you claim to be an "expert." Also, you claim to be a sorceress, but are "creeped out by witches." They aren't much different, and some people would use the terms interchangably.