Is your son/daughter participating in a sporting activity?

If so what is the activity and what age did they begin participating in this sport? Did the child ask to participate or did you ask them if they were interested and sign them up if they said yes? At what age do you think a child would know if they like doing a particular sport?

I am trying to explore the sport options for my 4 yr old daughter and I am curious what other parents have done in the past and present.