Havlíčková, who competes for Dukla Liberec , has mainly participated in junior races since 2015. At the 2016 Winter Youth Olympic Games in Lillehammer , she finished 17th in sprint, eighth in cross and seventh over 5 km freestyle. In January 2017 in Nové Město she became Czech junior champion over 5 km classic, in the 5 km mass start race and in the sprint. Her best placings at the 2017 Junior World Championships in Soldier Hollow were tenth place with the relay and ninth place over 5 km freestyle. At the Nordic World Ski Championships 2017 in Lahtishe achieved 11th place with the relay. In the following year she came in the Junior World Championships in Goms on the 11th place with the relay, on the fifth place in the skiathlon and on the fourth place over 5 km classic. At the 2018 Winter Olympics in Pyeongchang , she ran on 59th place over 10 km freestyle, 43rd place in the skiathlon and 11th place with the relay. In the 2018/19 season she won the U20 overall ranking of the Alpine Cup and took 20th place in the 15 km mass start race, 12th place over 5 km freestyle and ninth place with the relay at the 2019 Junior World Championships in Lahti. In January 2020 she started the World Cup for the first time in Nové Město . She came in 60th place over 10 km freestyle and 56th place in the subsequent pursuit. Her best results at the Junior World Championships 2020 in Oberwiesenthal were 11th place with the relay and seventh place over 5 km classic.
Mountain run
Aside from cross-country skiing, Havlíčková also takes part in mountain runs in summer . In 2016, she took fifth place in the junior race (U20) at the World Mountain Running Championships in Saparewa Banja and, after adding up the individual results with the Czech team, won gold in the team classification. In the following year, she narrowly missed a medal at the European Mountain Running Championships in Kamnik as an individual fourth of the juniors, at the 2018 World Mountain Running Championships in Canillo she was 13th in this age group. In 2019 Havlíčková won in her last U20 year European mountain running championships held in Zermatt with a 51 second lead gold in junior races.