I tried twice in my early twenties to transition. Both times an utter fail. Ms Grace summed up the many reasons well.
I Just Wasn't Ready
Or, more like ill equipped, emotionally, to take on the whole package that comes with transition. It is a lot more then just popping a few pills, which helped some. But.... Shame, Guilt, negative self esteem, zero self worth are tough to shake.
Even 7 years ago when I started this phase. HRT helped a ton to keep me alive. To restore my hope in me. If I didn't put a lot a hard work into healing me, finding a support group, eventually a therapist, reading a ton of self-help books, etc. the experiment would have ended the same as the previous ones.