Smelling a little bit of propane is not dangerous for your health.
However smelling propane around your house could indicate a leak unless you just smelt a bit of propane from a propane bottle.
You're not gonna get sick or die from smelling a small amount of propane but breathing in too much propane could be harmful.
Although I've read online before that the propane is a non toxic gas when inhaled but you certainly don't want to be breathing in a lot of propane.
The smell of propane comes from an additive that makes it smell so that you can easily detect a propane leak but before the additive is added to the propane the propane is odorless.