Although I am a Catholic I wouldn't consider myself overly religious. But I do understand why people don't like to use the phrase, "Oh my God" because to some it is taking the Lord's name in vain. I would think "oh my gosh" or "oh my goodness" should be fine though. Or just saying "OMG" like people will text I wouldn't have a problem with. Little people sure can repeat things fast though, my son was in the room when we were watching a adult drama that happened to mention the word "porn" once in a conversation and my little guy repeated the word twice right after hearing it which of course made me go cringe but I tried not to react too much as I do notice if you make too big a deal of it kids will want to say the word or phrase more. Thankfully he seemed to forget this word later so hopefully he has forgotten it.