I20s are only for high schools... youger kids cant get them... the government will not issue an I20 to child not in high school. however if your child has the I-20, then there should be no problem getting the f1.... however, since he/she is only 12, then you will need a guardian for her... otherwise she cant remain in the country alone. i suggest you ask someone to be her guardian while she is int he usa, and you can come and go on a tourist visa... you can stay up to 6 months with your tourist visa. then go back and come again a few weeks later... that way you can be with her during the school year, and in the summer she can go home with you. when you go for the interview, just say that she will be staying with Mr/Mrs. xxxxxx, and have a letter from that person stating they will take responsibility for her while she studies in the usa. then at the same time ask for a tourist visa for your self so you can take her there and help her get settled. then you can come and go, while she remains in the usa for school. good luck to you.