What is the beset age to start an internship for photography?

It appears you have a passion for photography. I would approach your local newspaper and ask for their advice. Bring along a digital portfolio of only your very best images. Track down the papers director of photography, or lead photographer, and ask for an interview. Tell them why you want to meet. At this point, I would not worry about the age issue.

Emma, you could try cold calling photo studios in the Bay Area. Some of the small boutique ones might give you a shot. I also think you should follow Mr. Wuerth's advice as well. Your portfolio is very important. Be selective with it. Make sure the pictures you include follow the rules but don't use that as your only criteria. Portraits and photojournalism are two different animals and require different portfolios. If you can try to apprentice in each. Age is not an issue. Talent and drive are. Remember it's not the equipment but the person behind the camera that makes the shot.