Assuming the financial aid offer is need-only (i.e. not merit), it will likely stay constant if your parents income stays constant. If you have a sibling in college right now who will graduate, your aid is likely to go down once your parents are no longer paying tuition for that sibling. But all things being equal, need based aid will stay consistent as long as nothing happens to alter the income side of the house (or a large inheritance, winning the lottery, etc.)
Term time employment is a job that you would have while you were on campus while school is in session.