Kibiwot made his international debut at the 2013 African Youth Athletics Championships, taking fifth in the 2000 metres steeplechase event. He raised his profile in 2015, first by winning the Kenyan junior trials and then by winning the gold medal at the 2015 African Junior Athletics Championships, seeing off Ethiopia's reigning Youth Olympic champion Wogene Sebisibe Sidamo in Addis Ababa. He capped that season with a persona best of 8:22.10 minutes at the London Diamond League meet, ranking as the second-fastest under-20 athlete that year behind another Kenyan, Nicholas Kiptanui Bett.