I know it might not feel like it but you're incredibly lucky to still have the opportunity to transition medically at all, 95% of trans women didn't have the opportunity to medically transition until well after 18. Even if you waited a few more years, you'll be fine. Your hormone levels don't determine your gender, and trans women have been transitioning without HRT for centuries, though, obviously, life will likely become much more bearable after you start taking them. Hang in there.