Sketches - Web Design Planning

I have made some very rough sketches to plan my website on MS Paint. It is a very simple program which I am very familiar with, but I just wanted to set everything out very simply in order to build on it later.
This is the layout for my main page, or the basic layout for all of the pages. They will differ with respect to the content, but the logo and navigation bar will stay where they are to make the website consistent. The background is a pale green - I wanted to build my website on greens and pale yellows because I think of those as natural colours, rather than oranges and reds which I think of as overbearing and unhealthy.

I plan to have a quiz on my website to make it more interactive. The quiz is aimed at children and could be taken on the website or printed by parents or teachers and used as a resource or lesson inspiration.
The quiz gives rough guidance as to whether the child is healthy or active enough and suggests how they can remedy this.
I hope this will entertain the young viewers and give them clear goals to achieve in order to take their lifestyle into their own hands.
I also plan to have a video on my website. The video needs to be short and entertaining, featuring someone of the same age as my target audience, i.e. someone between 6 and 12 years old. It needs to be short to keep the viewers attention span.

These sketches help me to visualise a rough idea of how my website should work and what my content should be.