There are three different age groups: A-Class (16-18), B-Class (13-15 years) and C-Class (<12 years).
As a junior, you can compete up until you are 18 years. It therefore will compete in the junior class while you are young. It is usually the best youngsters who will compete even junior contexts. When you are 18 years to compete as a senior.

There are  four different branches in synchronized swimming: solo, pairs, team and combination. A full team consists of eight people, but it could be down to 4 if you do not have enough people to cover the eight locations. The combination is one of up to 10 swimmers who swim both teams, pairs, trio and solo. One can thus combine the number of swimmers for the 5 min long program. If you are a youth or junior will compete in addition to its program in figures. Figures are when doing a combination of movements, without music, and alone in front of a panel of judges.