Should travel with a group I don't know?

One of my friends called me about a trekking trip. One of his friends was going on a group trek (around 15–18 people, including his cousins and friends) and asked my friend if he wanted to join, so my friend invited me too.

But now my friend has some stuff going on and backed out of the trip at the last moment. His friend still called me and said I should join anyway if I want to, and that it would be fun.

Should I go? I’m worried that I won’t fit in or that it might be awkward since I don’t know anyone there.