On Mondays, I answer questions frequently asked by those considering a return to the Catholic Church. How do I know this stuff? I was away for more than 30 years myself, and am the co-author of When They Come Home: Ways to Welcome Returning Catholics, a book for pastors and parish leaders interested in this ministry.
I’ve been going to Mass, but I don’t know how to get acquainted with other people at my 
parish. I don’t want them to know I was away for a while.
You just might be surprised to learn how many of them were “away” for sometime. Maybe the people sitting next to you at Mass are back for the first time in years. Maybe the lector or Eucharistic minister have only been active in their faith for weeks or month. Heck, I was on parish council within weeks of returning to full communion with the Church, but I wouldn’t recommend it.
Consider going to an activity that seems non-threatening and doesn’t involve an in-depth knowledge of dogma and doctrine. Maybe it’s a lecture on Pope Francis’s encyclical on the environment. Or maybe it’s helping out at the parish food pantry, or being part of a young people’s prayer gathering. Or, talk up the doughnut lady or guy after Mass if you’re uncomfortable going to a table and sitting with strangers.
In any event, if you don’t want to talk about your journey just yet, simply say you’re new to the parish when asked (that’s true) and ask questions about the other person. Listen. He or she just might appreciate the interest.
