Jepkorir made her international debut at the 2011 IAAF World Cross Country Championships, where she finished ninth in the junior race and was a non-scoring member of the silver medal-winning Kenyan team, which was led by the winner Faith Kipyegon. The following year she was runner-up in the 3000 metres at the Kenyan Junior Championships, which gained her selection for the 2012 World Junior Championships in Athletics. She placed sixth at that competition in Barcelona, which was won by her team mate and national champion Mercy Chebwogen.