I always regret selling my first bass. If you are just starting out, and still have your first bass, keep it! I would love to have my first piece of wood with strings that I eventually learned to make sound come out of. At the time it was a matter of having to sell one piece of gear to get another, so I didn't have a lot of choice in the matter, but in hindsight, I should have tried harder to hold onto it.
The reason I had to move to another bass was my hands were starting to get bigger, so I needed something with a longer scaled neck.My magical first bass was a Fender Musicmaster, which was a short scale neck. I still remember the smell of the case when you would open it up. I looked online tonight for a picture like the one I had and the best (and the coolest) picture I could find of it was this one of Kim Gordon of Sonic Youth playing one. I of course did not look as cool playing it as she does, unless a chubby 6th grader who secretly wished he was Chuck Berry is your idea of hip.