What you are going to have to come to terms with is that you have set your sights on learning to play what is arguably the most difficult musical instrument ever invented. People often think that since the theremin has no physical interface, such as a keyboard or a fingerboard, that making music will be relatively easy because it will just flow naturally through the free movements of their hands and arms in the air.
If it is your intention to make sound effects, or to create music that is "aleatoric" ("chance music" produced by random waves of your hands) then the theremin is ideal. If, however, you want to play melodies with accuracy and precision then you should be prepared for a lot of hard work.
When RCA first introduced the instrument in 1929, the publicity brochures said: "Anyone can begin to play the theremin on the same footing with the finest cellist, pianist or other instrumentalist in the world! A child...an elderly lady...a skilled musician...a blind man....all can learn to play this incredible instrument with exactly the same facility! It is destined to be the universal musical instrument; people will play it as easily and naturally as they now write or walk."
This was a lie, and a misrepresentation of the instrument that RCA was forced to drop like a hot potato two years later. A more realistic appraisal of the difficulty involved came many years later from Clara Rockmore, the greatest thereminist who has ever lived:
"The theremin is much more difficult than the violin, which I played for years.......People expect to go over to the theremin and IT PLAYS. No! It takes hard work, sensitivity, sensibility....attention to detail. You have to learn it and it's not easy. The music comes from the heart, the mind, and years and years and years of the study of music."
No one should be discouraged from taking up the theremin - it is an extraordinary and rewarding instrument - but to avoid disappointment I think people should realistically consider the difficulty of the undertaking.