Some items I forgot......

I wouldn't buy a new bike for my first bike. While you're learning to be a competent rider, You'll probably dump it while trying to start it forgetting it's not in neutral, dump it at a stoplight, have a couple of minor issues misjudging turns, etc...

There are some advantages to a used bike. They're cheaper, and if you decide you don't want to ride after all you can resell it without getting hammered on the price, and those minor scrapes everyone gets in their first years of riding won't freak you out. Also, the lower price leaves you more money to spend on safety gear. Yes, you can buy a helmet for $39.99 in JC Whitney, but do you WANT a $30 helmet protecting your head?

When you do start riding, in addition to the helmet, long sleeves, long pants, boots and gloves are a minimum. Denim is OK, leather is better. (If I had been wearing leather I might have avoided a little road rash and one heck of a lot of cactus spines in my behind) People who ride wearing shorts and sneakers are statistics waiting to happen.