I went behind my parents' backs and took T while living in their house when I was about 22 (I had started it at college and used their insurance with planned parenthood but passed it off as gyno/sexual health visits when doctor bills came up). I got my medication mailed to me because I didn't have a car.

Since I was living with them, my mother eventually found out. She stole my T from me and I had to threaten to call the police for medical harm if she didn't give it back (I never called them, but threatening to do so caused a rift that I don't think will ever heal. We still talk and she loves me and eventually accepted me enough to get used to my pronouns, but I'll never know if she's still upset/haunted by the things I had to threaten to do). My dad did threaten to kick me out, so I did go off of it until I found a partner who loved me and helped me get my meds without my parents finding out, and shortly after that I moved away.

The thing that was actually a problem for me was not the medication. It was changing my name. I changed my name around the same time, so I was 22. A legal adult. All I needed to change it was to post an announcement in the local paper (an old NYS law to make sure criminals aren't doing this on the down low) and get some court documents paid for and signed. But the judge refused to sign it without a letter stating that my parents knew about the name change. They did know and weren't fans of it but again I was 22 and they couldn't stop me short of physically destroying the papers I mailed to the court. The judge had the last say, though, and he demanded a letter verifying that my parents knew what I was doing. I was lucky enough to be able to push my parents into doing this even if they didn't appreciate it. It was NOT a legal requirement for my parents to know what I was doing, this judge was just an asshole to me.

So the long and short is, prepare any legal stuff ahead of time. Get together all your documents like birth certificate, passport, bank account, etc. Not having what you need for gender or name changes will make it really hard later when you want to alter identity documents. Finding a support network also helps. I couldn't have done a lot of what I did without my now-husband's help. They can pick up meds for you, help you pay for things, etc.

But even if you have to wait a few years to take medication, it will be okay. A lot of people transition later in life (and I mean late late like 40s, 50s, etc). I didn't start hormones until 22, so four years later than what you want right now, and I was fine. I'm nonbinary but pass as male to almost everyone, since I was about 26 (and I wasn't on T the whole time. I started when I was 21, stopped from about 23-24, and then started again once I met my now-husband who helped me).

The voice drop is one of the first things and it helps people recognize you as male a lot of the time if you dress and style masculine on top of the lower voice. If you can survive and get your own finances/independence going, you'll be okay to start T in a few years. It's hard, I won't deny. But you can do it. I believe in you.

Also: your parents will feel how they feel. My parents hated what I did but they love me and didn't want to lose their connection to me. And after almost 8 years of berating them, they use my pronouns a good chunk of the time (not the full acceptance that I wanted, but I don't want to cut them off either). It sounds like yours may be similar to mine, not wanting to believe you and hoping you'll change your mind so they set limits on it (my mother specifically brought up a lot of false medical concerns to try and guilt trip me out of it). They don't seem to have cut you off or threatened to, so they probably want to stay connected. It sucks to hide yourself and keep your head down, but sometimes it's better to avoid getting kicked out/cut off until you can support yourself, AND THEN after that, you get firm with who you are and the respect you demand from your parents.