Since someone else mentioned it in a different context recently: Would DIY be helpful here? Or too risky? Not what you want? You’d need to hide the supplies somewhere out of your parent’s reach, but the immediate and long-term benefits of starting early might be worth it.
I see, just wanted to add after the last post, since it sounded like full DIY may probably too risky from your description: The physical changes will be visible at some point and things might end up badly once they put one and one together.
So if anything, that’d only leave puberty blockers: They’re more expensive than just injections, but they’d stop any further T-related changes from occurring and it’d take many years before anyone would notice that something is “off” and by that time you’d already have had legal agency for a while. (Naturally, you’d have to procure them illegally since you don’t have parenteral consent.)
(If you wish for physical changes toward a more feminine appearance getting your T down as soon as possible is unfortunatly pretty important for a good long-term result at your age.)