They got all their gear together and set out.
Are you excited about participating?
To be honest, it's not suitable to my nature.
If you have a phobia or physical limitation, you should reconsider participating. If you're with friends and the activity is a little challenging, it's good to go outside your comfort zone.
I have anger management issues and hate the outdoors.
Then it sounds like you might want to take a pass on going with them.  There's no sense in doing something that's going to make you miserable.  Your friends will understand!