Well depending on if you have a part time job while attending college you may find you will have more free time then you realize, unless you are also balancing social commitments, to paint and build your miniatures but don't slack off while attending. If you really buckle down in the period of time before college classes start you should be able to paint an army but this will all come down a few things. 1.When do you want to start playing by (You can do a little bit here and there eventually your full army will take shape) 2.Which army will you be collecting (Horde armies with lots of models will take much more time and effort then small elite forces) 3.Quality level of each individual model (will you be doing tabletop standard or shooting for much higher quality) 4. What PL or Points were you hoping to play at?(More Points More Models) 5. Most importantly do you want to really buckle down to achieve this specifically before you go to college. I do not want to dissuade you from joining this glorious hobby but its really going to boil down to time, realistically you could assemble and paint a necron force (Leadbelcher spray, washes, couple colors) in a little under a week but it really does depend on the army and how much you love it which will drive you to keep going. I wish you the best of luck.