Initially, I found it quite different flying friends and family to flying on my own or with an instructor. The added responsibility of taking care of someone else's life for an hour or two increased the stress and concern levels for me. Don't forget that you're learning something new when you start flying with friends.
So my advice is to do it when you feel confident yourself. I'd take just one person with you for the first few times, and try to pick the mate you think fits with it the best. Even your best mates can be unpredictable in a confined space 2,000 ft off the ground! Once you've completed a few trips and after a few weeks, you'll have the increased confidence to take another and really enjoy it.
Final point, a guy I knew at my flying school filled a 172 with 3 mates as soon as he got his PPL, and only just made it into the air at the end of the runway....his enthusiasm to take mates up clouded his judgement (no weight and balance checks), he was overloaded and luckily got away with it. Do your W&B checks, but my rule is in Cessnas and cherokees, always leave one seat empty.