The 38-year-old, who will continue to play for the Orlando Pride in the NWSL at club level, also explained why she is "very calm" about the decision to step away.
"I'm very optimistic about the development we're seeing with young athletes," she said. "We have a very qualified team, with very talented girls and, over the years, you'll see that it really is what I'm talking about, it's very fertile ground. For this reason, I feel very comfortable saying: ‘Look, I'm passing it on to you, I'm passing the baton, and you carry on this legacy'."