Hi Valentina!
Welcome to the club! First of all, an old Fender will always have a certain collector value over the Alembic. That's just the way it is. But old Fenders are not consistent in quality or sound. You may get lucky and find one that plays and sounds great, or you could end up with one that has neck problems (twisted or bowed) that can't be fixed, and buzzes and hums. The Alembic is obviously of superior quality and sound. It's really up to you which sounds, plays and looks better.
I would recommend keeping the Alembic and perhaps finding an old Jazz Bass later. Old Fenders are easy to find, but a really good one is not. Every Alembic that I've tried sounds and plays great.
The most important thing is to try the Fender before deciding. If an instrument doesn't play or sound to your liking, it doesn't matter whose name is on it - it is worthless.
I can say all this from personal experience because I own a very large collection of Alembics and a very large collection of Fenders (mostly Jazz Basses).
Best regards and again, welcome to the club!
Rami