Glad you enjoyed it! Anyone can attend PyCon US. There are people from all walks of life and skill levels. If cost is an issue, PyCon US has a generous financial aid program. A caveat: some prospective attendees in other countries have difficulty getting visas.
You shouldn't feel that way at all. I don't think I've ever had a bad experience meeting people at a conference. It has actually been the opposite. Many people are there to make connections (and have their own doubts as well). You might be surprised at how receptive they will be. Also, many conferences actively promote inclusion. See the "Pac Man Rule" attributed to Eric Holscher which was referenced at PyCon US. https://www.ericholscher.com/blog/2017/aug/2/pacman-rule-con...