96 cavalier rattling at front passenger side

i'm not sure if this is serious or not, but it just started:

- start the car, a rattling noise can be heard when sitting inside the car, when idling, coming from around the front passenger wheel
- outside the car, i can't hear much of anything
- when the car is still but revved, the rattling noise (again from sitting inside) goes away
- when the car is dropped back down to idle, the noise comes back

i don't know anything about the car's structure (in terms of mounts or anything), but does this sound like anything to worry about?

it kinda sounds like it COULD just be old age, shit on the car is becoming loose after years and miles of driving, and starting to creak and shit, keep im mind you drive one of the cheapest cars in the world, mine kinda "rattles" every time i go over bumps, the dash, the hubcaps, the backseat, my car just sounds like a giant pile of loose plastic actually... (and its 2 years younger then yours)

that MIGHT be it, and if it is it, you have nothing to worry about