Neppérus studied at the School of Journalism in Utrecht and (tax) law at Leiden University. She was a member of the Royal Students Rowing Club Njord and rowed in the Dutch rowing team. At the Olympics, she was active as an umpire at the rowing. She later held various administrative positions in the rowing world, including the Royal Dutch Rowing Federation (KNRB) and the International Rowing Federation. In 1991 she was appointed an honorary member of the KNRB. She also worked for the Revenue and the Ministry of Finance. She was a board member of the VVD in Voorschoten from 2000 to 2002. In 2002 she was elected into the municipal council of Voorschoten. From 2004 to 2007 she was also VVD fraction leader. In 2005 and 2006 she worked for the Inspectorate (IVW) of the Ministry of Transport. In the 2006 parliamentary elections Neppérus was on the candidate list of the VVD and was elected into the House of Representatives of the Netherlands.