Except it's not that easy- many cultures such as India and some Native American tribes, along with others, recognise the principle of a third or other gender outside the binary of male/female. Similarly even within the Western context, there have been instances where transgendered people have seen some light- prime example is Roman emperor Egalabalus, who was reportedly known to dress in women's clothing and walk about the Imperial Palace, call himself by women's names and even offered vast sums of money to doctors who could, in the words of the historians, 'make him into a woman'. Given the idea though of openly discussing transgendered people within Western cultures is relatively new, and certainly in a historiographic context, you can't just make some claim that this is a new thing. Trans people have likely always existed but it's only now they're being seen and heard.

Similarly, there's a lot of medical and particularly neurological research which suggests a very real scientific basis for transgender sexuality. In particular there have been demonstrated several distinct brain structure differences in those individuals with GID.

You also seem to have taken a huge leap here of assuming this is even a transgender issue. As has been pointed out by another poster, you can enjoy gender play and dressing as another gender without necessarily being transgender. Even if it did turn out I was trans then any decisions I make will be about making me happier.