"You know, as a mother, you worry," she said.
However, seeing the passion and the drive that her daughter has shown in fundraising and training for the ride has lessened her anxiety.
"I'm getting used to the idea now, because she's getting a lot more comfortable riding, and running and getting herself in condition," Jo Ann Robbins said.
"She thought it would be a good cause and something that she believed in and wanted to do," she said.
"When she puts her mind to something, she usually does it," she said.
Robbins' group will leave the Inner Harbor June 2 after an early morning ceremony during which all of the riders from all of the routes will gather for a dedication ceremony and simultaneously dip their bike tires into the harbor before departing for their various destinations.
"I've never done anything remotely like this so I am just completely pumped," Robbins said.
She said the riders will honor those who have been diagnosed with, or survived, cancer daily during the trip.
"Every day, we have a dedication ceremony in the morning and we'll write the names of the people that we're remembering that day on our calves," Robbins said.
"Remembering them keeps us going, because you'll be sore and you'll be tired and everything but you have to keep going," she said. "Because if we don't keep going, cancer will win."
To make a donation to Robbins' ride, go to her website at 4kforcancer.org/profiles/sarah-robbins/.