Welcome to the hobby! Glancing over the equipment you want to purchase, I think that will be a good start. Don't get your hopes up for movie theater quality with it, but it will prove to be a base. Much like you I started building my system very slowly. I got my first receiver when I was 16, along with 2 KLH speakers. Over the years I added a piece at a time. I added literally a price at a time, weather it be a CD player, a TV or more speakers. It took me roughly two years of work to get to 5.1, and then I quickly did another upgrade to 7.1. For the last several years I've been working on getting rid of the original components and upgrading to higher end equipment. All that being said, my original KLH (are they still in business?) speakers are still in use 13 years later. Today they act as my rear surround channels.
Have fun with it. As much as the instant gratification of buying a $5000 system is fun, building it slowly and growing it has its perks.