the very first man who came in this world ws muslim,all the prophets from ADAM (A S) to MOHAMMAD pbhu wr muslims,later on their followers changed their theachings n became jews,christians etc
Not true. Prophet Mohammad started Islam only in the 6th or 7th century. This is well documented, so don't even try.
It is agreed by all muslims that there is no Islam without Quran which itself was revealed to Mohammad - Obviously therefore, even going by muslim legend and beliefs, there were no muslims before him