Here is my 2 cents worth. I did both. I flew in the summer and went to University in the winter. It worked well for everyone. I was heading back to school just as things slowed down and the company was looking to lay someone off, so they were happy. I made great money by university student standards, plus logging approximately 500 hours every summer. It was an easy choice at the time because no airline was hiring, so I was not missing any flying opportunities while being at University.
Which brings me to my second penny worth. Seniority is just about the only thing that matters once you are hired. If an Airline career is what you decide you want... get on ASAP. Do not wait because once the wave of hiring is over, you may wait a long time for another chance.
As the russian controller in Edmonton Centre always says....Good Luck!