[pace]

Normally, I'd say it's hard to decide and I would tend to recommend to finish your studies. But in your case it's different: You are studying CS and getting an Software Engineer. You are on a market where the demand is so much higher than the offer, thus there's no need to signal your skills through a degree. Anyway, you'd learn much more and faster when doing a startup. Or in other words: many reference projects and/or a great Github record is more worth than a degree (and most good devs I know havn't a degree).

One thing I'd change: you location, Belgium seems to be nice, but you need lots of peers in physical distance. So change to a city with a vibrant tech community (Berlin).