Muslims make a ignorant claim that Paul created "Christianity" and that Christ nor his 12 disciples were called "Christian". First of all it's rather ignorant to try and claim Christ himself would follow himself and need to be called "Christian". Its just as absurd to suggest the 12 disciples would have called themselves "Christian". The 12 disciples were JEWISH and they dont change their Jewish faith and identity just because they recognize (Yeshua is) Messiah.
"Christian" is a (label of) identification of those NON-JEWS OF THE NATIONS that Know Yeshua as Messiah. Jews that embrace Yeshua today dont call them selves "Christian" (unless its to relate to believers of the nations) they call themselves Messianic or nazarenes. Those the never studied Jewish culture may struggle to understand but its rather simple. The etymology of the word "Christian" centers around its root which is GREEK (Christos-Christ) rather than Mashiach/ Moshiach of the HEBREW. Jews Never identify themselves according to Greek standards.
-Acts 11:26- "The disciples were called Christians first at Antioch." Antioch is modern day TURKEY and again its OBVIOUS that this is a title adopted of believers of the nations (goyim) Not Hebrews (Jews) like the 12 Apostels. (this culture was fluent in greek and used it to identify themselves as believers, no issue there). The gospel wasnt even taken to the nations until AFTER the cross when Christ sent his disciples to the nations. Christ was sent to ISRAEl (JEWS) so muslims show their ignorance be reciting the flawed thinking of their imams that actually think spreading this rhetoric about how "the 12 Apostels werent called Christian" is a point. Thats basically what muslims do to attack Christianity. They cant attack it head on they first have to find weak minds then pervert the scriptures and the faith in order to then create a flawed arguement in order to try and make the faith look bad. Islam has nothing of value to offer. You will be hard pressed to find ONE revelation that is of value to all mankind that ONLY came through the ideology of muhammad (the quran).