maybe you can add some adsense link list under/between the blog archive and category list.. don't over do it, just start simple and then test it.
I just have to say you should be SO PROUD of yourself!! I am proud of you! That is an excellent blog, and you leave the reader wanting more. Good Job! I think you can go ahead and add your ads anytime. I did mine right away so the reader never noticed them. Thats one of the important things about placing your adds. Blend them in nicely, and don't have too many. My blog Believe in my signiture I feel show a good example of ad placement and style. If you are nervous of how it will impact, start by adding just one small add and see what happens. Good Job though, keep up the good work, and I think you will really help a lot of teens with your knowledge! Its nice to see a teen do something other then video games on the internet : )