Ahouanwanou debuted internationally at the 2012 African Championships in Athletics in Porto-Novo, Benin. She competed in the heptathlon and finished sixth overall with a points score of 4983, 941 points behind the gold medalist. Ahouanwanou's best result in an individual discipline was fourth in both the javelin and shot put. At the 2012 Summer Olympics she competed in the 100 metres hurdles. She placed eighth out of nine competitors in Heat 6, setting a new Beninese national record at 14.76 seconds.