IOWA CITY — Rotary International got its start 115 years ago — with its Iowa City offshoot joining the century club in 2015 — and the average Rotarian reflects that deep history, as much of its 1.2 million global membership is older.But many of the 35,000-plus rotary clubs — including the Iowa City Noon Rotary Club, boasting about 300 members — want to diversify their ranks by, among other things, including more young people.“The challenge is really a worldwide challenge for rotary, and I think a lot of service clubs like it, to keep growing and keep some of the younger folks — younger professionals especially — aware of what rotary is and what it can do, both for their career path and then also for that kind of human necessity of belonging to a community and feeling part of something bigger than themselves,” Ryan Bell said.