I did it my junior and senior years and just recently graduated college and am instructing full time at the same school. Here are my thoughts:
If you are struggling with school now or are having difficulty pulling the grades you want, instructing will probably make that worse. You could, however, be the type of person that works well with stess; when you are busy you don't put things off and get it done right away. If I don't have much to do I actually get a little bit lazy, so instructing and going to school wasn't a bad thing. But it gets very busy and stressful at times. How close to campus is the airport? If it's far and your work and class schedule don't mesh very nicely, you could be driving back and forth between campus and class multiple times per day. If your flight school gets more students will they hire more instructors or just pile onto the current ones? While I was in school I had 5 students at one point, 4 most other times. 2-3 is very doable and wouldn't be a problem for most. I was ready to pull my hair out when I had 5 and was trying to write papers and study for tests.
In summary, if your school is used to having student CFI's and work with you, it shouldn't be a problem as long as you manage your time well. But when it becomes test time you don't have the luxury of not teaching for a few days. In my opinion, if you taught and went to school while pulling decent grades it is a good indication that you have it together. Not bad to add to a resume. Good luck.