My hands and arms are veiny, too, and the bones on the back of the hand stick out a lot. I have serious skeleton hands. Definitely got worse as I lost weight. My tiny mom has them, too. Mine don't track all the way up into my forearms, just up into my wrists.

On the plus side, I can now give blood which I couldn't before. :)

I've noticed too and I love it.
I've always been a little obsessed with veins (yeah, all my friends think its weird too) and my veins still aren't as pronounced as my mom's- it's the one part of aging I'm really looking forward to.
One of my best guy friends has really nice veins all around his arms and he thinks I'm creepy for being so engrossed with him. I'm mostly just really jealous that guys have better looking veins than we do.