Welcome . You meet fellow airsofters by going to airsoft sites and playing. Do not worry about turning up alone, most of us start out that way, and you will soon get talking to other players. We are a fairly friendly bunch and do like taliking about guns, kit, (some especially about technical stuff) and our experiences. Through this forum I have met up with several airsofters and played at different sites. So you could say that this forum is a place for lonely airsofters to meet. You do not need to be part of a team.
Best bit of advice - just choose a site, rent some kit, and go play. See how you like it; I wish that I had gone sooner as it is good fun. In the meantime read the sticky posts which contain lots of very useful information, use the search function, and ask questions.