I went through a lot of this stuff you're talking about back when I was figuring myself out and questioning.. Or mostly for me it was about breaking my self denial more than anything else, deep down I knew already at the time when I started to look into how to feminize my body. It was not a game, not for fun, it was about becoming my real self all the way.
Btw, drop the "ism" from transgender because it is not an ideology, its about existing as yourself... If you're transgender, that's who you are, its not an ism. It really irks me when people keep on calling in that, some big names and people with media visibility do that too and its bad for us all. Any gender identity is what it is, none has to do with ideology at all. Sorry for nitpicking, but words do matter as they're often used to oppress.
To me a certain sign is questioning, there must be a reason that you're seriously wondering about this stuff. Majority may play with the idea "what if I was a woman for a day?" type of thing, but to seriously questiong what and who you are is telling in itself and to be taken seriously. Self search is always worth the effort in life anyway as what are we here for if not grow up and evolve as humans. And normalcy, is being transgernder woman abnormal? Minority are, but I think its very much normal and natural part of human condition as why would we exist otherwise?
I dunno if I'm biased to talk about this or an oddball in a flock of strange birds because I'm more than likely also intersex because my body is strange, to me questioning and figuring things out and finally acting upon it came quite naturally and it was a very long process which started already when I was little kid... But reading your posts I see a lot of myself in it, including body building background and such, I did that too and for me it was largely a failed attemp at male compensation. I also absolutely loved the exercise but the lifestyle itself was too high maintenance and then my haleath started to fail, I likely closely avoided completely destroying my wrists/carpal tunnels and so on, I'm rambling, I've talked about this a lot in my thread if you're interested in digging into it.
I think questioning is healthy, there must be a reason why you keep asking this stuff. In the end no one else can answer your questions but yourself. Go back to your past, your memories, when did this start, has it been consistently growing in your mind for years or came up just recently? How does the idea of transition make you feel? Scared? Excited? Consider what are the pros and cons if you do it, that's a big one to think of, you don't want to regret your decisions, but more than likely regret of not figuring yourself out would be worse. What ever it ends up being, questioning is the right thing to do as this stuff is clearly bothering you.