I'd like to say for my own peace of mind that, while I'm a bisexual who tends to prefer girls, I'm not exactly a "prepubescent boy in a dress".
I'm curvy and somewhat out of shape (I'm not fat either, by any means). I'm into jeans and skirts and dresses too, although I hardly find the ones I feel comfortable with. I have an ever growing collection of squared flannel shirts (not blouses) that makes my mum flinch every time I get a new one (I confess that seeing her pained expression gives me a great deal of pleasure). My attachment to my converse trainers is almost legendary. I like high heel shoes, but I try not to wear them often because I deem them not practical. I have an almost pathological love for boots. I rarely use jewellery on my wrists (unless you call jewellery a hair-band and a couple of memorabilia thingies of a couple of metal gigs I went to) or my neck (except for a heart shaped gold choker my parents gave me for my 16th b-day). Mostly, I wear small ear hoops, but I might surprise my friends and family with long, feminine earrings now and then. I rarely wear any make-up (I'm always in a hurry and I hate carrying a Mary Poppins-like bag, if at all). I'm rubbish at proper manicure care, and often my nails are seen without polish, or it on varying stages of peeling off.
And yes, most of my friends think I'm not lady like enough, but also not enough to be labelled as a tomboy; even less to be called a full on dude. I'm not lady like enough to drink pink cocktails, eat only salads (or just a half of them). But I'm not dude enough either, because sometimes I'm a little bit too clingy and a bit much of a hugger and touchy-feely and whiney and I like to cuddle -but only sometimes-. I swear like a sailor, and try not to trash talk people -females specially-, and when I get mad at someone (except my mum, of course) I try to solve it by taking them for a beer and a chat and then everything's right again.
I don't exactly like the labels lesbians categorize themselves under, but if I had to describe myself into one of them, I'd say I am a versatile chapstick-lipstick kinda girl.
So, no. Those styles are not about the only options for formal wear that apply to lesbians/bisexuals at all. You say you look like a boy? Grow out your hair. Use pins or bows or something just as girly on it. Wear a scarf instead of a tie if it matters that much to you.
Or simply, just tell those straights to suck it up or fuck off.
