I'm afraid to let a religious friend know my beliefs, what should I do (details)?

So it may not be a big deal, I hope it’s not. But a long time ago when I set up my Playstation account username, I put the name atheist in it cause I was dumb lol.

Sony and the Playstation network don’t currently have a way to change your PSN handle besides buying a whole new console or starting a new profile, which would start me over from scratch.

So a friend of a friend wants to invite me as a friend on playstation, but I know he’s religious and so are a lot of the people we know and I grew up with them. I’ve gone to church events with them but never told anyone I wasn’t religious.

Basically I just don’t want him to find out and tell everyone or have him look at me differently. What should I do?