Unless you somehow decide cycling's not for you:
You will inevitably find a bike you think is really awesome, ride it around for a couple weeks thinking you're the bees knees and within, oh, 2 months tops realize that your bike isn't that cool and start dreaming of a new build. We're all constantly upgrading because we bought something and then we find out there's something cooler and better.

My point is that whatever bike you buy is a starting point to let you dip your toes in to the sport/culture. You will upgrade it and change it and almost assuredly move on to a newer frame if you stick to this sport, so don't cough up too much money or put too much thought into your "perfect bike" until you've got some mileage in your legs.

Oh, and for the record, my first road bike was a vintage Bianchi and I loved that thing to pieces until my boyfriend backed his car over it.

We replaced it with a newer Trek and that bike's carried me over the finish line first twice in the last month. Brands are very preferential.