Thank you bennevis for your advices.
I'm thinking of taking a Trinity music performance diploma. With this diploma, do you think I'll be qualified enough to teach?
I have a performance diploma (ABRSM) but I don't feel qualified to teach, because that diploma is all about presenting yourself as a performer, and showing your skills and knowledge of the kind of rep that performers would play. Nothing related to teaching at all, as far as I remember (it was a long time ago), but the technical requirements are very high and you have to play your pieces from memory (after all, you are going to be a performer
, and audiences expect very high standards of performance).
Whereas the teaching diploma requires you to know the kind of repertoire that would be suitable for students of each grade, how you would teach specific stuff depending on how old the child is etc; but the technical requirements are much lower for the teaching diploma, and you don't need to play pieces from memory. (Check out the difference in the technical difficulty of the pieces you have to play for each diploma.)
I'm basing this on ABRSM - I have no knowledge of Trinity, so you'll need to check up on their website to see what their requirements are.
I think that if you are self-studying, you'll have a much better chance of getting the teacher's diploma than the performer's one. It took me two years of weekly lessons with a concert pianist (after getting my ABRSM Grade 8 Distinction) to further improve my technical and musical skills, practising in all my free time while at university (about four hours a day), before I was ready to do the performance diploma.
As to whether you're qualified to teach with a performance diploma, if parents will employ you, that's up to you if you have the knowledge and skills. (My last teacher had performance diplomas but no teaching ones, but then he only taught advanced students). After all, in the USA, you don't even need any qualifications to teach piano.......