@Chimaera ah jeez look, as a parent and former deviant youth, no please please don't do this.

Just use a different device. Chatting with people online your parents explicitly forbid is not going to end well. Closing browser windows as soon as they walk in is obvious and frankly irritating as heck, infact I set one of my kids computers to save a screenshot to the desktop once a minute to remind him to be smarter about it.

As a once quite deviant youth, I'd suggest using connection sharing to another device such as with a hidden local pivate wifi and then, on top of that, using something with no local storage for your terminal. I used a laptop with no hard drive and no battery and a wifi card with a mac address my father had never had in his dhcp logs when I was learning about coming out. My mother had a habit of ripping devices out of my hands and reading my journal, etc. Any device with ddr3 ram or newer should work fine.

The local library is a great resource as well (depending on local attitudes). You are not the first oppressed soul seeking truth, and there are correct ways to do it. They can help. Learn about good opsec and be safe.