As a small child I was absolutely convinced that people in the olden days lived their day to day lives in black and white, and that they walked slightly faster than we did today (assuming a frame rate thing?).
I'm gonna put this one down to my understanding of how TV worked as a ten year old. Everything before colour TV was black and white... therefore everything was black and white. Makes perfect sense.
What about you?
It's not too late. There's no real procedure to changing your name, you just have to start using it.
Yes, the whole "deed poll" thing is needed for getting a passport changed/updated, but that's just a letter that declares you're no longer using the old name, for which free legalese style templates are available online. A couple of signatures from people you know that can vouch for the change and job's a good'un.