Everything points to the first flush of youth. New site, lots of new content and google loves this. Now time as started to balance as your rightly say, to settle the site to where it naturally sits as a new kid on the block, but not that new.
What-ever you do, do not tweak, if Moz page rank scores are good for your keywords etc, as this will end up with you being totally confused about the stats you are starting to see.
Make sure each main page scores well for your keywords and build good content and update regularly to your main category pages. Products pages are static, so use your entry pages to add fresh content. Improve each page where you can.
Penguin is cannot penalise sites without spammy links, so this is not the problem if you don't have any.
Remember Google is about quality end user content, fresh and unique.
Hope this helps on the journey. Look forwar to many more questions in due course I am sure.
Bruce