Rachael, we all doubt ourselves all the time, I think for me enthusiasm counts for so much, I think that and passion is what needs to come across, and you are in your post so carry on with what you are doing
I really believe the power of positive thinking got me through it, I saw myself getting an interview, then saw myself succeeding and I did it!!!
If I can anyone can, don't think what if they don't want me - think how it will feel when they say - welcome to the course
Good luck hun