Ah, Seraphyna. I recognize you!
Well, first and foremost, I've felt canine ever since I was a child. I only began to actually wonder if there was something wrong with me or different around late elementary school, but for awhile I dismissed it. Eventually curiosity got the better of me, and I shared my feelings with a few friends. One online friend kindly helped me, as stated in the OP.
I acted out (rather mildly, but still definitely noticeably) on my feral feelings, especially when I was younger. I was on four legs instead of uprigjt as often as possible until I was like... eight, nine? I vocalized like a canine. I bit and scratched. I roughhoused like you may see a dog do. I "played" wolves with my friends, but got rather upset when they called it a game, as I didn't see it as such, insisting I was a wolf. I had various other canid behaviors.
I had this behavior beforehand, but as soon as I was introduced to wolves, something just
clicked. I had an obsession with them, and not in the way you see "wolfaboos" doing on the internet. I surrounded myself with wolves, identifying with them before I even knee the word "identify."
As soon as I heard the term "therianthropy," I jumped into the community headfirst, as I immediately knew that was me. Shortly afterwards, I went through long periods of questioning and self-doubt, as other people seemed "more legit" than me, as I didn't have big shifts, etc. However, I now identify as a suntherian, who only has small fluctuations from the middle ground like a sliding-scale.
Gut feeling always brought me back, though, and is ultimately what makes me sure I'm a therian. Behavior is just another factor.
I'll admit that my phantom limbs only appeared after learning about others having them. However, mine are faint to begin with, so whether they're a case of mind-over-matter or the idea of them simply not occuring to me until then is anyone's guess. <!-- s

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Anything else?