What is Little Tackers, and is my 4 to 6 year old too young?

Little Tackers is the programme for children aged 4 to 6: fun and games at a Tackers centre, where children learn basic movement skills through play at a sailing club. Australian Sailing describes it as a beginner course of about 3 hours. It runs in small groups of no more than 6 children, with close supervision from qualified Tackers instructors. Children receive a Little Tackers completion certificate.

The only prerequisite listed is that the child is 4 to 6 years old.

Source: https://www.sailing.org.au/course-finder/60 and https://www.sailing.org.au/news/tackers-program-kids-boats-fun