One of the more experianced members could answer this better but from my experiance their are a few concerns. Yes signal interferance is very very possible. It can cut your signal and shoot your plane out of the air. Many of the new, more expensive systems have technology to prevent this like the spektrum series of controlers. Sounds like you are flying at an RC field? If so then the other flyers have this same concern. Their is probably a board were pilots place their AMA card and take a marker "contains the frequency number" and attach it to their antenna. The best advice would to be to ask the others who are flying. I would extremely recomend having him start with an instructor. An instructor will show you the ropes and tell you all the important info about frequency and flight line and flying protocol as well as teach you how to fly. Here is a link that has tons of usefull information http://www.modelaircraft.org/ while you are their you need to get an AMA liscence. This is for your and everyone elses protection.. It's like insurance.

Good luck and have fun