Well, here I am in the MTF forums again.
Lulz.
Yeah, eighteen is definitely not too old to transition, so I see why you're looking for other excuses even if it's simply to find any at all. I think as people we're all different, but afraid of being "too different" because most of us have this tendency to find comfort in others. It doesn't really bother me when I'm not much like some other transguys, because there's some of them I really wouldn't want to be like....like at all. Plus, I don't really consider this my journey into becoming a FTM, but more of journey into becoming myself and finding what makes me happy. That's what really is important. Basically, you should realize you're not like all of the people in the community you may try to identify in, but that shouldn't something that holds you back from being true to who you are. I used to try to rationalize too.
I didn't particularly like my female body, but a lot of other people did, so to some degree, I started to think there was something deeply wrong with me for hating it. Not to mention, it doesn't really bother me as much to look at my body as it does some other transfolks I've talked to. I'm fine with my body as long as I cover my chest...well, for the most part anyway. I don't avoid showering for the sake of not looking at my parts. I never hyper-feminized, but I tried to be androgynous for a really long time, but I would exploit myself because I was insecure and feel terrible for doing so afterwards in a really feminine way. This was out of self hatred and denial. I've always wished I were cis...and actually cis-anything really, so I didn't have to deal with all of these problems. I feel for you.
I didn't realize I was trans until I hit puberty. I never identified with being female much as a child, but I certainly don't think I identified myself as anything gendered really. I was just me. I don't thing someone's assigned sex really mattered to me all that much until I hit puberty. I seriously didn't even think about that stuff or why it would've been important beforehand, or at least not that I can recall.
I actually suppressed my masculinity before I decided to transition, so I'm sort of in the same boat with you. It wasn't readily apparent that I was "manly" a couple of years back until people got to know me. As I said, I was androgynous. I don't think it's weird for guys to wear makeup though, especially if it's just coverup for a blemish or two I do that sometimes. I'm not a gay transguy. I'm totally into women. I don't associate trying to make myself look good for the people I want to attract as anything all that feminine really.
:]
Basically, your means of trying to rationalize this still doesn't work. Everyone is different. If you do decide to transition, don't let those petty things get to you. This isn't a cookie cutter world, m'dear.