This is funny, because when I first cut my hair short, I was worried that I would look too much like my younger brother.
Now, I'm not sure why it bothered me. I look a lot like both of my brothers, and each of them looks more like me than the other, though we all look obviously related. People who look at baby pictures can't tell me and my younger brother apart. So it was pretty likely that after I cut my hair or emphasized my masculine features, I'd look even more like my brothers, especially my younger bro. In fact, it's creating a bit of a time warp - until T catches me up to my real age, I appear now to family members far more like my brother was some years ago.
The upside is that I never feared that T would make me look unfamiliar or like a different person. I know pretty much what different versions of me would look like with the effects of male hormones.
The downside is that we are so similar and recognizable (and have not changed since childhood) that we are routinely recognized by total strangers who know our siblings. I was once approached when I was in female mode in a different city from where my brother lived by someone who went to school with him K-8 saying, "You must be[your brother's name]'s sister!" It's not horrible, but it means I do need to keep track of whether my brothers have chosen to out me to friends and acquaintences of theirs or not or if they are hoping to keep it quiet/stealth. Otherwise, if someone approaches me thinking I am "other brother," I don't know how to play it.