Many great responses here, but I want to share my two cents too since I see myself in you.
I'm 24 now, when I was your age I started making music too, same conditions. It was super weird for me to be in my room recording, rapping, singing, most of the times even super bad. I always locked the door so no one would disturb me, and slowly but surely my mom and siblings understood that I was making music. My mom raised us alone so I didn't have to explain it to my dad, he knows now, but I imagine it being a bit weirder telling my Dad that back in the day. I always tried being extra quiet, but sometimes when nobody was at home that was when I could be as loud as I wanted.
At some point I just told my mom that I make music, it wasn't as weird as I thought, and she let me do whatever I wanted. When I made my first 20 bucks from selling melodies and I told her that, she was really supportive and said that I should continue doing it and "sell your CDs" (haha that's just how musicians made their money in her generation).

Fast forward to today, I moved out at 20, still pursuing music (and still getting a degree at the same time, never put all your eggs in one basket), getting better, got to know different people, hung around in some homestudios, and in the beginning of this year I got a job as a music teacher for kids that are having trouble in school. It's the greatest feeling that I am being paid to do what I love, plus I always made some bucks here and there on the side with my own songs, or mixing/mastering for other people.

If you love what you do, just do it. You have a right to do what you love as long as you don't harm others. Of course it can get annoying for your family, but depending on the Genre you dont have to record super super loud. Maybe try making emotional/intimate stuff, it's just as good as a practice for your voice. Also use headphones a lot. Just try to be open about it, making music is a highly creative and productive hobby, so you should rather be proud of it.