If you want to study FX Makeup, go to Cinema Makeup School. People come from all over the world to study at Cinema Makeup School. Hands down, they have the best FX, Character, Prosthetic/Appliance Master Makeup Program available.
While it's good to know and understand basic beauty makeup application, if that is something you are not all together interested in doing, don't waist your time and money by taking intensive study work in basic beauty makeup. Go straight into the Master Makeup Program at Cinema. They'll give you the basic beauty makeup education; however, this program is geared more for people like you that know they want to get into FX makeup.
Since you are an esthetician, you can pay to join the MAC Pro Program, you'll get a 30% discount on the product and you can take some classes taught by MAC's Master Artists; however, I would not call these 'classes' a formal education. These classes are geared towards the working pro artists, not for someone who is just starting out. Don't waist your time. It sounds like you know what direction you want to go in, and I say go for it..... Of course, there are more schools out there that teach SFX makeup; however, few are as respected, and as well known as Cinema Makeup School.
Start by getting the education first, everything else is ancillary. I sincerely wish you the best of luck.