It's perfectly legal in just about every nation in the Western World. Indonesia where you live, I'm not so sure. As dances12 has so wisely advised you, be discreet. In addition to not showing your face, I'd advise that you make sure that there is nothing in the background of any photo you post that could be linked to you.

For all I know if you are up to 18 year old and are your pics not stole or from any underage I guess its not breaking any law that I know