I have passed 12th with 69% with pcm 64%,& so much confused about which course will suit me either Btech orfashion desining ?

You are not interested in machines but you are good in sports....are you creative and love designing ??If yes then go for Fashion designing or you may choose industrial/product designing which will utilize your knowledge in science.

It's so obvious that out of the two modes of learning (tutored and self-learnt), a self-learning approach suits you better. this is amply displayed in your skill in sports and guitar and lack of marks. Obviously based on current information, btech wont suit you. For the latter kind, design could be

you have scored good marks i can suggest you to consider going for B Tech course (Computer/IT) your basic knowledge can be applied for any field like fashion