At least in the Case Study homepage, there is a lot of commented out markup in the source, and an entire section where it looks like it was done in an HTML generator - because you are not using the Cascade at all, and every link re declares the same font-family over and over.
Something else you should consider is looking into this course: http://discover-devtools.codeschool.com/
It will help you understand what is going on when debugging webpages.
I know it's hard to be doing stuff that likely few people your age can relate to. Adults will dismiss you because of your age, and there isn't much you can do about it aside from continue to develop your skills so when you are taken seriously, they feel stupid for doubting you.