PE - CRUNCHY CRUNCHES

well today I had PE lesson.first we had running test.as usual, I was the slowest runner.I did it for abt 12s.after that we did crunches and push ups.basicly I cant do crunches although I always do crunches -failed crunches- when warming up.I can do push ups better.but I think Im not lucky today as I fail my crunches -I did 0 crunch- and I only did 24 push ups.for push ups,I really could do more but I just had difficulties as my knees were moving.they couldnt stay there.I kept moving to the back and finally I missed twice,so I failed and only get 24 ones.oh my God,I am really bad in PE.I have no favorite sport,I have no talent in sport,and I even have no interest in sport.well I always try to do my best.I have the interest to try but then its really useless,I fail everything.oh maaan...how come I cant do anything about sport..?everyone does like sport.everyone is good in PE.but me?I even cant swim wtf.what is my best?gymnastics maybe.I can do SKJ (Senam Kesehatan Jasmani - Body's Health's Gymnastics) quite well as I dance and move my parts of body.guess what,I used to hate dances.modern dance,particularly.but now I suddenly love it.dancing,moving my parts of body..doing new things is really interesting.I♥dancing!!well lets back to laptop.I really need experts to help me,teach me how to do crunches.I think I could have some problems with my bones or something so that I cant do crunches,but I dont hope so.I must put more effort in,maybe I must practice more on holiday.every Monday maybe.ah I really hope I can do much better in PE..