Almost everyone I've ever played with is an amateur. Hell, I'M an amateur!!! If by amateur you mean not experienced in playing a lot of tournaments or doesn't go to professional card rooms or casinos regularly, or play regular high dollar home games with other skilled players. In my experience, amateurs mostly play tournament style home games. Anyone who's regularly playing cash games is at least a step above an amateur. But they may still be fish, or sheep, going with the original analogy. So regardless, no matter how big you win, I think most of these sheep are going to just assume you got lucky. They're not sophisticated enough to recognize skillful play over luck. So go ahead and take 'em! They'll invite you back anyway, just to get another shot at you.
Maybe don't shuffle chips or try to MAKE yourself look like a pro. But still play your best.