Change the design of your first website, update it on regular basis, get some visitors and then you can put your code without any hesitation.
Well if you have a reason to think that Google would have a problem with your second website then I would suggest you don't use it. It is allowed by the Adsense TOS to use the code but if your website is not appropriate for Adsense you will probably get banned...
Hi Smithy, You can use this Adsense code upto 200 websites or Blogs. Noproblem, but the sites are under Google TOS. All the Best. Rammanohar.
Due to lack of proper content google rejected that, if it is not violent no problem, use this code for that also,
so probably best to look at the TOS for the guidelines and try to ensure your website is within them.