Just go with what you know and are comfortable with, and make sure you make it possible to change various parts of your architecture later on. It's easy to ove

Just go with what you know and are comfortable with, and make sure you make it possible to change various parts of your architecture later on. It's easy to over-think and over-engineer when starting out, and it's usually not that hard to switch to a different DBMS later on or even use a modular architecture that allows you to build different parts of your application in different languages as you go along. The real danger for you, right now, is that you won't make it to 1.0, not that you'll have to write it all over again from scratch.