I think that's fairly common to be more in love with the first thing you tried. IME, I had played Fallout 1 and 2 as they released. Was exited for 3 when it came out, and while I thought it was a great game, it didn't feel like Fallout. New Vegas feels like the Fallout I know. 4 even feels like a good representation, though not as deep.

But I might feel as you do if I first played 3. Then all the other Fallout games would feel weird. lol