OP, your friend that said a 600 would be a good starter bike is spot on. As long as you respect it's power and don't do anything stupid it'll treat you well and give you room to grow. 250's might be great for learning but after the first year you'll be bored with it and want something bigger so just get a 600 to begin with and save yourself some money. Definitely get a fuel injected bike. They are much easier to maintain especially when winter storage is involved. My starter bike when I started riding a few years ago was a Honda CBR600 F4I. Just remember that even the 600's are absurdly quick and should be treated with respect.
Best thing you can do as a first timer is take a "Beginner Motorcycle Safety" class. Not sure what they offer in your area but here's a link to one of the big sponsoring groups for these types of classes.
Motorcycle Safety Foundation