In the Uk it is a bit different: depending on the gymnasts level, age, and club.
Most gymnasts will compete routines made up of compulsory skills in the spring - between 1 and 4 competitions between February and April. The skills are dependent on which track (regional, national, or elite) they are following.
In the autumn all gymnasts will compete routines made up of voluntary skills - again between 1 and 5 or 6 competitions between september and december. The elite track has seperate voluntary competitions to club track gymnasts.
This year, the autumn season begins on 19th september. My gymnasts aged 6-9 may compete in one competition this autumn for experience. In the UK formal competition only begins in the year you turn 9.