Don't go around asking companies to do something illegal for you. I agree that hustling is good, but not when you put the burden of your success on someone else.
Working on projects with people you meet/know isn’t illegal. Getting a real job would be, but not this :)
If those people are in a company and that company benefits from your work, they could still be breaking laws related to internships and child labor.
Unpaid internships are illegal except under some very restrictive conditions.
That said, these things don't seem to make it to court, so you're probably not risking anything by doing them.
Surely someone will appreciate your ambition and give you an opportunity, just don't expect it to fall into your lap. No one is listing internships with the expectation that someone pre-college will fill the opening but don't let that deter you. I say this as someone who landed an internship at 17.