After your first job advancement, can you still get skill points after level 30, or does it stop giving you skill points?

You will always get skill points after your job advancement. You need to use all the skill points earned at level 30 and below before you can take the test. If you go over 30 before taking the test you still get the skill points and they do not have to be used. They can be held over until after the job advancement. You may use points obtained in 2nd job/3rd job on first job skills, to do that you click the skill book and apply, however, it is not recommended to do this.

http://strategywiki.org/wiki/MapleStory/FAQs