there are a few smith's here younger than you, if Anyone gives you a hard time Becaue of your age, let Glenn know, He knows how to deal with idiots, as we were all young once, its because someone older took the time to teach us, that we are smithing today.
Now... remember that giving you a hard time for not listening or being dangerous is allowed
and should be expected
OK back to the real issue, 17, meaning you don't own or have any real control over th garage. To address some of the issues with sound sound, USe Egg crates ( left over from the eggs you ate for breakfast ) have been used for years as cheap sound defusers, just tape/glue/staple them together in strips, mounting them on a old sheet is a good idea too. Hang them on the walls like a curtain when you need them, they only adsorb high pitched sounds, BUT they cut down on the sound reflections, making it quieter outside the room, and inside the house too. carpet does not have to cover all the surfaces, even a small piece here and there will help deaden the room too.
The low frequency can only be delt with by Mass, meaning sand filled, very thick walls, and true sound proofing is NOT cost effective for most people.
Work with what you can, Hook up with local smiths is always a help, many have open forge times for you to go and use the groups equipment too.
Welcome to the insanity of Metal working.