Which is the Best Course in Online Fashion Design for Kids?

My 14 year old daughter is interested in taking a course in fashion designing. I have been looking through a few different online fashion design for kids courses, but haven’t decided which one would be best for her. I have narrowed my choice down to two different programs. One of them lasts for three months and one lasts for six months. I think the six month course has a lot more to offer, but I am concerned that she will get tired of it and end up not completing it. Which would be most fitting for a teenage girl who is also playing sports in school?