Matthews was born in Atlantis and attended high school in nearby Malmesbury. From there, he was selected to represent the Boland Cavaliers at the Under-16 Grant Khomo Week in 2010, kicking 12 points with the boot in his two appearances.
After school, he moved to Pretoria to join the Blue Bulls academy.[3] He made ten appearances for their Under-19 side during the 2013 Under-19 Provincial Championship, scoring tries in matches against Leopards U19,[4] Golden Lions U19[5] and Sharks U19[6] during the regular season, and another one in the final to help his side win the title with a 35–23 victory over the Golden Lions.[7]
Matthews then played for UP Tuks – the university team affiliated to the Blue Bulls academy – in the 2014 Varsity Cup, scoring tries against UCT Ikey Tigers[8] and Maties[9] in his four appearances. He played in eight matches for the Blue Bulls U21s in the 2014 Under-21 Provincial Championship, with tries in matches against Leopards U21[10] and Sharks U21[11] during the regular season. For the second season in a row, Matthews was the member of a title-winning team, starting the final of the competition where the Blue Bulls beat Western Province U21 20–10 in Cape Town.[12] He was rewarded with a contract extension by the Blue Bulls, ensuring he would remain in Pretoria until October 2016.[13]
Matthews scored a try in a 29–all draw between UP Tuks and UFS Shimlas in the 2015 Varsity Cup[14] in one of three starts in the competition, but suffered a knee injury that kept him out of action for the majority of the season.[15] Despite his injury, Matthews signed a further contract extension until October 2018.[16] He returned to make a single appearance for the Blue Bulls U21s attempting to retain their Under-21 Provincial Championship title, starting a match against Eastern Province U21.[17]
His third Varsity Cup campaign saw him score two tries – against UJ[18] and CUT Ixias[19] – in five starts before making his first class debut, starting in the Blue Bulls' 14–19 defeat to the Eastern Province Kings in Port Elizabeth[20] in the 2016 Currie Cup qualification series. After a second start against the Pumas,[21] Matthews scored his first senior try in a 38–39 defeat to Griquas in Kimberley.[22]