After a year without a partner in Canada, Belbin moved to Detroit in 1998, where she was partnered with Benjamin Agosto by their coach Igor Shpilband. In the 1999–2000 season, they won a pair of medals on the ISU Junior Grand Prix series and finished 4th at the JGP Final. They went on to win the U.S. junior national title and then took the bronze medal at the 2000 World Junior Championships. In 2000–2001, Belbin / Agosto competed again on the JGP series, taking gold in all three of their events including the Final. They appeared on the senior level at the 2001 U.S. Championships and won the silver medal, qualifying them for their first senior World Championships, where they finished 17th.