Airsofters can sometimes seem like abrasive pricks online, but when it's time to play we're generally super supportive. I think you would be applauded for coming out to play and do something you love. There's a kid out there who is basically condemned to a wheelchair, and his local team set him up with a special rig so he could roll around murking fools like a mini-tank. It's the coolest thing I've ever seen.
Anyway, to make a long story short; don't be discouraged. There are many kinds of play-styles that might suit your mobility level perfectly. Sometimes it's nice to have a guy holding shit down with tons of MG fire, not moving around too much. The most important thing is to forget what people think and just get out there to have fun. If someone tries to give you a hard time about it, tell them to kindly fuck off and just keep doing your thing, because airsoft is something for everyone, not just for elitist assholes.
I'm sure you will be suprised by how much help and support you get from other players. If you run into the occasional douche-canoe, don't let it get you down. Just snipe that sucker.
"World's laziest sniper"