Hi there

Take a deep breath, and let me be the first to tell you that you are not alone.
I haven't posted here very often, and I certainly haven't ever told my 'story' to anyone so this might get a little long, please bear with me. But after reading your post (actually, I almost replied to your post in Chrystal's topic, but refrained not to derail the thread), I just had to post - because your words resonates with my own experiences so clearly, at times it feels as though you could be describing my own teenage years!
Let me just start by saying that while growing up, I had many of the same experiences that you describe. Though I don't recall my early years very well, I did later hang out with more of the 'nerd' crowd.. I didn't have many female friends, I was drawn to computers, roleplaying, etc... and I wasn't very feminine, which could mean that I was just good at pretending, more tomboyish, not trans at all or.. oh, this really isn't easy at all, is it?

I am currently 25 years old, and a good way through my degree in Data Engineering (I started on CompSci as well, but it was too boring for me haha), which is certainly a male dominated field. Looking back though, I mostly just followed what was expected of me.. I liked computers, I got a technical high school degree (we have a different system here) and started studying 'something to do with computers'.
I think I was 12 or 13 the first time I put 'gender change' into google and realized that it was actually possible.. so I cannot ever have been very comfortable with my gender. I have probably been drawn to trans resources online every few months since then, always guiltily pulling away, as the idea of transitioning seemed so impossible, so surreal, it was a dream and nothing more.
From lurking on this site for years, I know that for some of us the answers are very clear cut. Transition, or suicide. But for most of us, it's not that 'easy' (did I just use that word?).. and we will forever be haunted by doubts, no matter what we do. Can I live the rest of my life as male?.. at this point, I think probably.. but every year, every month, my dysphoria seems to get worse, which makes me think that maybe I shouldn't. I am also terrified of 'ignoring' it, 'macho' it up, perhaps even get married.. and realize in 20 years that I am at the 'transition or suicide' stage, with far more obligations, and having to 'look back' and wish I had done it 20 years ago.
My biggest fear with coming out is having to confront my parents, because I am sure they will protest 'We have known you your entire life, there is no way you can be trans! Your room was always a mess (^_^) and you are a geek, what girl does that?!' - okay maybe not exactly that, but you get the point. And I don't have any answers, because what if they are right? What if this is all in my head, and I am simply delusional?
Also, I don't really think our habits, interests, friends etc. determines whether our 'inner' personality matches that of a male or a female. Most of it likely comes from social expectations and I certainly don't believe that cis females are in any way less inclined or able to pursue technical fields, or be 'computer geeks' - only that expectations and interests elsewhere often makes it a less attractive option.
Sorry for all the rambling! I suppose the TL;DR version would be that you are not the only one searching, not the only one with doubts. I can still hardly believe that I am going as far as I am, and actually exploring my feelings to the degree that I am. Because let me be honest, this entire thing
terrifies me. I think that is normal, but it also gives me great great respect for those further along in their transition because I am not sure if I have the courage.
Oh, and like you I have been called girlish jokingly before (I have somewhat long hair with a male cut and use a straightening iron every day - otherwise it curls like crazy ^^) and rather than make me uncomfortable, it just makes me smile inwardly with a warm feeling.. so I think perhaps that should be taken as a sign that we are on the right track?