There are many laws in most european countries regarding financial services, banking, investment advice, anti-money laundering rules, lots of regulations to observe.

There's a reason why so many Forex brokers are located in Cyprus, Malta, Jersey (islands, not USA), lax rules and bribing opportunity.

Just because you're young, run Linux, know php and want to do something means that you can just ignore all regulations. It doesn't impress the authorities if you build things like banks and trading platforms and start taking and paying money from all over the world, they'll be on your ass as soon as they find out about it.