The title makes it obvious, is this a good idea? I've been looking for a robotics simulator in languages i know (i know ruby best, then c++, then python -- want to strengthen here--, forget about javascript, but i know it). 

i found something called pyro, but it probably doesn't fit my needs (listed below). 

In my last university term i learned c++, then they took me to RobotC (which was only about 2 months of the term). Pyro seems similar but now i want something different.

I need something that allows to import graphics, allows 3d environments, allows to easily modify actions robot can perform. Also provides other things necessary for robot programming, like a sensor.
Panda 3D is a good language to write your own robot system in.  It's written by CMU people, so it's very clean and makes a lot of sense.  It allows you to import very complex models from Maya or Blender.  It supports 3D environments.  Although it has its own scripting language for running actions (animations) imported from your modeling package, I prefer to write my own robot driver.  It supports three different physics engines, including its own basic version, Open Dynamics Engine (ODE), and most recently Bullet.  Although it supports collision detection, which allows triggering, it is an animation and graphic rendering system, not a robotics system per se, and so you'll have to craft your own sensor simulations beside or on top of it.  All in all, though, it is quite satisfactory.  Good luck.
Panda3d Robotics