Advice
You shouldn't be nervous about your internship. The most important thing I learned is that everyone you're working with, even your boss, doesn't expect you to learn everything in one day. It simply takes time and 3 months inst enough over the summer. Also, take on as many projects as you can. If executed correctly you can gain the trust of your coworkers and boss and hopefully will get a chance to come back or maybe even a full-time offer after school. Lastly, don't just sit there and collect a paycheck, try to learn as much as possible, even you don't end up working for that company you can still take the things you learned and apply them elsewhere.