Depends when her birthday is as to what year she goes in to. My daughter is also 15 and goes in to year 10 this year 2018. Year 11 here would be born between 1st July 2001 and 30th June 2002, Year 10 in 2018 would be 1st July 2002 and 30th June 2003. Ali has given you good information with regards course structure for 11/12. However, entry to the subjects is usually granted based on performance in year 10 so I would say doing the exams in the UK won't do your daughter any harm. Does she know what she wants to do? Does she want to go down a Uni path or more of a vocational/work path?