Given this statement, I believe it's extremely unlikely that you're a TS woman. Gender identity does not change during one's lifetime; actually it is usually formed by age 3. Our identity is the essence of who we are, and it is very difficult if not impossible to ignore completely. There should have been signs throughout every stage of your life. And in fact the statistics bear this out: the 2015 US Transgender Survey (PDF link to survey), which to date is the largest survey of trans people in the US (27,715 respondents), found that 98% of people surveyed said that they began to feel their gender was different from the one on their birth certificate by age 25. Only 2% began feeling differences past age 26. If you had no clue all the way up until age 54, and you just happen to be a TS woman, you are a tiny fraction of a tiny percentage of people. It's statistically possible, but extremely, extremely unlikely. (Figure 4.3, page 45 in the survey)age noticed page 45.JPG
It's possible that you're still transgender. Maybe you have a non-binary gender identity. Maybe you're two-spirit or gender fluid or some other multi-gender identity. And maybe you repressed that partial female aspect of yourself. But, if your gender identity is completely female (which is what a transsexual woman is), then I don't think it would have been possible for you to have been totally clueless about it for 50+ years.