Yeah, it's always a good idea if you have some question.

However, according to Google's suggestions for adsense, the placement is perfectly ok.
https://google.com/adsense/support/b...y?answer=17954

If you're afraid that it may raise some eyebrows at Google, you can add another line break or two on top of Adsense and make sure you have something like "Sponsored Websites" or "Advertisements" so that your visitors know that it's not "part" of your site.

Edit: Here's a quote from Google regarding placing adsense on forums and blogs:
As long as you make sure your users know those are ads and you don't ask your users to click on them in any way, shape or form, I think you'll be ok.