Do I need to pick up my luggage?

Ani, if you are flying on a single ticket, your luggage will be tagged all the way to your final destination and the airport personnel will transfer it to your onward flight to your final destination. However, if you fly on two separate tickets, then you will have to collect your luggage and to make new check-in... In any case, just to travel with absolute peace of mind, you will ask this detail at the time of your check-in at the airport from where you will depart to Xiamen.

One very important detail if you are the citizen of Netherlands... Since December 1st, the citizens of Netherlands along with citizens of 4 EU countries do not need a visa to enter China, so you are free just to queue for immigration without bothering you with permanent entry permit or similar. The only thing you will do is just to fill out Chinese arrival/departure card on board of your arriving plane to Xiamen.