I was moderately serious about stamps when I was between 11-15 or so... had a BIG album (Master Global)...and I had begun to specialize in Hungary.

There was an old man who was a dealer near me, and I also sent away for a couple of deals.
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(I also collected..(well, accumulated) matchbook covers even earlier..9-12 or so. Pasted them in cheap albums.)

Then from 19-23 or so, I got into U.S. coins. That can get expensive. Finally sold my 1909-1944 pennies.