Good luck! People sometimes make mistakes out of habit without meaning anything by it. I hope if that happens they'll apologise right away and it won't hurt too much, but of course you can't control your feelings...
Nothing wrong with identifying as transfeminine and nonbinary at the same time if that works for you. And of course if you ever identify as masculine/male again that would be valid too, there isn't any prescription on being fluid :) And if it turns out you're not fluid, well you seem really happy so whatever labels you decide to use for yourself, I know everyone here will support you :)