I started a new job last month. A team of about 20 (most similar age to me) who have all worked together for a few years. Obviously, I totally understand that they will gravitate towards each other but I have no idea how to act when they are making plans right in front of me and not inviting me. I am generally quiet until you get to know me so I'm finding it very difficult to settle in when they all have their in jokes and banter and I can't join in on most of it. Any advice?