I always wanted to try playing D&D and recently got a group of friends together to play online with on Roll20. No-one in the group has any experience playing D&D or any tabletop RPG before.
Our first session went very well, we started the Lost Mines of Phandelver campaign. However, two others from my group of friends who I initially asked to play have now joined in once they heard how well our session went. I naively said this was OK as I didn't realize the implications at the time.
Another player also invited a friend of his along from outside our group, as he thought this was OK considering I let the other two players join in mid-way through the campaign. This brings the total number of players to 7.
I could sense that things were beginning to drag along at an incredibly slow pace with 7 party members and combat took an age to complete. My main concern is that I want everyone to have a positive experience and I don't want to turn them away from D&D or similar games due to a bad first time.
Admittedly, it is mostly my fault for allowing players to join mid-way, but other than simply telling the three players that they cannot continue the campaign, what can I do to give everyone the best experience?