Frankly speaking, it may sound awful to pay something to anyone. But about the national service, you have a chance to defer it untill 38. And I would advice to use this option at the moment. If you regularly visit Turkey, and as you parents would have some property or noone knows what is gonna happen in the future... So it is completely up to you to keep the citizenship or leave it away. But I would suggest to use the defferring option at the moment and decide later as you would pay visa fee everytime you enter the country and you will have to follow the foreigner procedures all the time (if you regularly visit Turkey).