rattling on start-up

I just got my mazda5 yesterday with 7 km (5 miles). when I came in to show it to the folks they noticed a rattle when I starting it up. So I called the salesman today and he mentioned something about its a usual mazda5 noise and its something to do with starter or near the starter (it was not too clear as I was on my cell phone). its not a major rattle but it sound like mental rattling on metal. The sound seems to come from under the car near the passenger front side.

Should I be worried, does anybody know of this unusual sound.

Could just be a heat shield rattling when you start up. I've not noticed this Yet on mine and I usually start with the door open (in the summer) I'd have it checked again ( better yet have the dealer start a 5 that they have on their lot aned see if you hear this "normal" noise

I just traded in my Mazda3 and got the 5, it might be typical with 2.3 cause my 3 and 5 make the same noise