First off you need to look for a school that has a schedule that fits your needs. the ones that have allot of instructors is good because if you are busy and only have a few days to fly, then having available instructors for that day is very important. You can always reserve a spot, but CFIs are humans too and they get sick (including other things like weather etc), so you would be days without flying. I also recommend you look for a part 141 school rather than a 61 because part 141 can get you your license faster and that means less money from your wallet. Part 141 schools usually have better planes (maintenance wise at least) because the FAA is much more strict with them.

First off, do your research, if you wan't to fly for "fun" then I suggest you wait till you get out of college and start winning some money because that would mean that while you take your classes, you would not be constantly worrying if whether or not the flight will get back on time etc due to money issues. Schools tend to nickel and dime you so be ready to spend extra money even if getting back late was not your fault.

I am looking to do the same thing you are doing, Get a degree in Aerospace Engineering and earn my licenses on the side, unlike you however, I plan to make flying my life and have the AE degree as a plan B.