I suggest you contact the Cursilllo leaders of your diocese. Not knowing to what diocese you belong, I can not give you their contact information or refer you to a particular web site.
As you probably know, young adults (in the twenties and over) are welcome to participate to any Cursillo weekends. However, some dioceses provide also cursillos "especially for young people between 18 and 35". For example, here, in the Catholic archdiocese of Montreal, two such cursillos were held recently at St Jerome for young French speaking adults. (The first one gathered 45 young men, the second, 60 young women). Such weekends are usually well publicised on their cursillo website.
For younger people, there are several Cursillo-related Movements for teenagers. Some relate more specifically to 14-17 years old, others to 18-25). Some are for Catholic teens, others are sponsored by another Christian denomination. For example: "Teens Encounter Christ" in the Catholic Church; "Chrysalis" in the Methodist Church; "Happening" in the Anglican Church. You will find a description of a great number of them under our menu "Cursillo" and we refer to their websites under "Links" (where you will find the dates and locations of their upcoming weekends)
Congratulations for your concern and good luck in pursuing your research.