Truthfully I think at 13, male or female, food/nutrition is critical at the beginning of teen years for growth and stuff, I started fasting around 15 and I’m 18 now and I typically did 16:8 fasting (which was effective enough for me, teens generally have quicker metabolisms anyway) every once and a while I would go 24 hours but never more than that. Depending on your starting weight you might be able to do more but your body at this time might not be as forgiving, hope this helps.
If you want to reach your height, muscle, skeleton and intelligence potential. About 12 hours (a nights sleep). My advice is to not even think about weight reduction unless you have a real big problem with overweight, and even then Id advice against fasting. Eat healthy and excersise!
Time restricted eating (12 hrs) has research support for obesity in teens, which we are seeing a lot of– for example https://pubmed.ncbi.nlm.nih.gov/34835953/and this is not fasting, which I’m not promoting on here for under 18 (it’s also a sub rule).
There are some concerns about potential for a relationship with IF and eating disorders in teens. I wouldn’t want a teen to do anything more than 12:12 TRE without medical oversight. https://pubmed.ncbi.nlm.nih.gov/36368052/