Congrats to your new zeal as a stamp collector! I only recently reignited my own interest which had been dormant from when I was 14 or so until I reached 60+ years old. But in 2011 I did exactly what faces you now. I had several old albums with 1000's of stamps world wide and glassines full of unmounted stamps. What was I most interested in? What amount of time could I invest in my new hobby? How much could I invest financially? Was my interest to follow a topic, or build an investment? Or both?
Several folks have already emphasized that this YOUR choice. I decided to sell off all my worldwide stamps to focus on older US pre-1930.
Being focused works for me. While I love the British Commonwealth colonies stamps I decided for now to build the best US classics collection I can afford. Main thing is that you enjoy the unique qualities stamp collecting affords by combining information that is historical, graphic, social, geographical, topical, national -- or whatever you the collector desires.
BTW -- I buy my Scott Catalogues used at tremendous savings from library sales on
Amazon or
ebay. Enjoy!