It sounds very confusing and challenging for you, you are being very brave sharing this with your T. And I would think it's fine to stick to telling her about romantic transference, tbh she might well join the dots from there anyway.

It's really normal and natural to feel erotic feelings for your T. It doesn't mean you're gay.
And, if you are gay/bi/Demi/pan whatever, I really hope that, in time, you can feel that that's okay too, and give yourself permission to love who you want to love without fear.