Yeah, not talking too much is often a good plan if you want to keep things simple :)
Plus, stuff like nail art of course isn’t exclusively feminine. If I go out with (very) light makeup, in women’s jeans and painted nails, internally I’ll be overflowing with girl stuff euphoria, but to everyone else I’m just some dude. Since my body shape, face and hair aren’t remotely feminine (yet!), there’s not really much to code “woman”. I think I’d have to wear a dress and full-on eyeliner for anyone to notice.
Ah, that sounds like a weird translation then. Looking at the manga (I think the line in the anime was similar), Makoto says:
That is, “I want to live as me. I’m a boy but I like girly things.”
OTOH, as you say the reaction to being perceived as a girl (and trying to pass as one at school) is pretty telling. But egg prime directive, and all that.