Someone asked recently whether it's bad to seek "signs" of being trans from the past, and why or why not. This question is one which deserves to be more widely circulated. Within trans circles a fair number of people have an understanding of the situation and it's complexity, but it's something I think non-trans circles should also be aware of— especially given the recent publicity surrounding trans lives.
The problems are twofold:
A lot of people look for signs because they're seeking some sort of validation. The problem here is that you end up misinterpreting and overanalyzing your own life in search of that validation. It's not that the past cannot provide validation for your present, it's just missing the point. What we want (more often than not) is acceptance of who we are now and recognition for our current experience. There's more to current identities, pains, and experiences than the past that gave rise to them, so validation can come from sources other than the past. Moreover, it's all too easy for people to "validate" your past while simultaneously invalidating your present, so validation from the past is not stable. Altogether, none of this is trans-specific: it's a general problem with seeking retrospective validation; and it also applies to people who've suffered abuse, experience mental illness, have changed careers, etc.
The second problem is that, in overanalyzing our pasts in search of validation, we all too often end up reinscribing "standard" trans narratives. If our pasts do not fit the "standard" narrative then we will not find the validation we seek, thus we will call our current understanding even further into question, and this sense of invalidation will only make us feel worse. If our pasts only partially fit the "standard" narrative then, in search of validation, we will highlight those memories and background the others; thus denying ourselves the full actualization of our personal history, and invalidating at least in part who we are. And if our pasts (somehow) completely fit the "standard" narrative then, in holding that history up as "proof" of our legitimacy, we end up marginalizing and invalidating everyone with different narratives. Again, this isn't a trans-specific problem (cf., "standard" narratives of gay lives or depression prior to, say, the 1970s.); though it's especially problematic for trans people because of the dearth of public awareness that our narrative tapestries are as rich and varied as cis narrative tapestries.
There's nothing wrong with seeking support for your current self from your past memories. Doing so is, imo, crucial in coming to understand, respect, and take pride in our selves. The problems of retrospection are all in the mindset with which it is pursued. We shouldn't rely on "born this way" narratives in order to justify the fact that, however we were born, we are here now and in virtue of our presence alone are worthy of respect and validation.
Fwiw, I do very much value my "signs", and often share them as amusing anecdotes— both to foster understanding, and to destabilize people's preconceived notions. But I do not seek validation in these signs; they're just collateral: symptoms of, not support for, who I am.