I'll add my two cents-- Kudos to you Nibbles!
I'd definitely want to see more of your progress. I've always wanted to try casting metal things (well, I did help cast a horse shoe once when I was about your age, or slightly younger, but that was with immediate guidance of a blacksmith babying me through it. I don't remember what all went into what I did, just that it happened lol) but I dont have the time (or money) to make sure to do it right.
It's true- none of us are there in person to see that you have appropriate adult supervision and that you follow through with any and all safety precautions. Accidents can happen, even those with the smallest possible chance of happening still can happen, and that should be kept in mind by anyone of any age.
I was also not the "typical teenager" myself and at 14 was more responsible than most adults I knew, and know the frustration. Not that I didn't have my serious lesson-learning screw ups like any teen, of course.
I can't tell you how many projects I got into that I would seek guidance from those more experienced in the trade, only to be told it is too hard/dangerous/time consuming/etc. and not to bother. To add salt to the wound, I would see some of those people doing just about everything I knew shouldn't be done. Not that it is the case here, but as an adult and mom, I can assure you everyone is posting in good earnest, and keep the cautionary words in mind.
For every thing you do know, there is always/will always be more things you don't.
Extra kudos for aspiring to MIT and to work with NASA. Astrophysics and cosmology are my (in progress/ on hold) fields of study. Not quite engineering, but there is room for some overlap there.
Keep up the good work!