Design Help

Okay, so I want your honest opinion! I'm trying to choose a style for my website. This website is an educational one geared towards students in 3rd/4th grades. I don't need any help on the content at the moment, I just want your opinion on my design.

This is what my original design was:

https://atlas.colorado.edu/~weirichn/moonandbeyond.html

My class/professor said that looked more high-school-y so I wanted to change it, but not to anything to kid-ish...it is still an educational site. Here's what I've got right now. Let me know if you have better suggestions for color or formatting or whatever:

https://atlas.colorado.edu/~weirichn/moonandbeyond2.html

Thanks!!!

xoxox summ