Hi Dr. Architecture!
How do I get an internship at a firm? I did email one local firm after mustering up some courage but unfortunately I got turned down. They said they only accept university students. So what do I do?
Based on your email, I am guessing that you are in high school. Given that you may not have the skills many firms are requiring, obtaining an internship may be difficult. Thus, what is it that you truly want? Money, experience, or exposure to the profession to decide if it is for you.
I will argue that the latter is what you truly want. A firm may not hire your for an internship, but they may be willing to let you shadow for a day or two to better understand a firm and what they do. Be persistent and realize that you are still costing them money even if they do not pay you.
Also, there are other ways to learn about the profession. -- attend a summer program, read architecture books, attend lectures at a nearby program.
Start with obtaining Becoming an Architect: A Guide to Careers in Design -- there is full chapter of experience and how to gain it.