If I get my Private Pilots License before college, how far will that set me ahead, if at all?
Well, since you want to go to Purdue specifically, a good place to start would be the Purdue Professional Flight website.  I found this there:

FAQ: Students Coming to School with a Private Pilot’s Certificate. Is there an advantage?


Depending on each individual situation, a student coming in with their Private Pilot’s Certificate can be either an advantage or disadvantage. The only real difference is cost. Sometimes it is more cost efficient for a student to get their certificate from Purdue or an outside flight school. It is ultimately up to the student.