When I moved from the sticks to San Fran to start my transition, there were many that thought I was ftm. The entire time I lived there, people made that assumption, from a few months pre hrt to a few months post orchi, when I left.
Heck, I had a hard time trying to pass as a guy in school, long before minors were allowed to even consider altering their anatomy.
It just means you'll likely have an easy time passing as a woman when you blossom out.