Congratulations on finding a partner. :banana:
Over here, the couple have to dance in the age catagory of the older person. Having said that, remember TC that
she has asked
you. 
She may be a 'better' dancer than you at this point but she obviously thinks you are good enough, so don't think of yourself as the liability.
I don't believe you should be paying for all the lessons. It is a partnership, which means that as much as possible everything should be equal. Sorry to find a negative

but that aspect doesn't sit right with me.
A partnership of quality requires mutual respect. In most new partnerships, one may think (and actually be or not) better than the other
but if that is pushed into one's face then it can lead to many negative feelings. If you can, I would rearrange the financial agreement. If you have already made this arrangement though, that could be tricky. I would then put a time limit on how long you will pay fully, perhaps a couple of months, and then you share equally. The lady can't have it all her way - she already has chosen the coaches, albeit good ones, but still her choice. Please, don't think you aren't good enough and then get walked on.
She asked you.