Always add google analytics or some form of tracking the day you start any of your websites...you must know your traffic sources so you can find whats making you money and capitalize on that!
Don't worry. Just make your site as legal. Try to update your content regularly and that must be unique. Try to spread your site all over the web and earn a big amount of money.
The only reason you would be worried is if your traffic or clicks aren't genuine, if it's all natural then its fine regardless of CTR.
Its natural to increase visitors , if you are working on seo, backlinking and quality content posting.Keep it up.
if the clicks are genuine then you don't need to worry .But if the clicks are coming over and over from a typical ip then get ready for a ban from adsence.