I was 27 or so. Was into Topps and Bowman before that and I used to walk around the Holidome in St Louis when I was college age and look at pre war cards but I just did not know enough about them to take the plunge.
Then around 1988, I was at the St. Louis show and came upon a table of T206 cards that a guy had just made a find on and they were really nice cards. I bought a Wagner (Heine that is) that looked pristine (It later graded an SGC 80). So I can say that my first pre war purchase was a T 206 Wagner