When you were 16 did you know that employers use a college degree as a coarse filter when trying to get a manageable applicant pool? It would seem that your answer was most likely one of two. You were either ignorant of reality when making a huge decision, or you were the type to want to fight reality because it felt like injustice and you 'knew better'. Of course at 16 we all 'knew better' and if that's how it went down I'm sorry you didn't get better advice... but it's a personality trait that some folks don't grow out of, and if you've ever managed a team you know they aren't the ones you want to have around.
Anyway, this is not to make any sort of judgment on you personally, you have probably done more awesome things than most 24 year olds and may be nothing like what I described, but you asked: when an employer sees a resume without a degree that's a snap decision thought process they might go through.
The situation actually isn't that bad... most of the best jobs aren't "resume" jobs, they're "hey I know a guy" jobs. Networking is much more important than resume to getting a good job - especially at startups!