Well, there may be a variety of reasons for this, which - without knowing any more about the club - may include one or more of the following:
- Club specialization: The coaches and more-skilled fencers at the club may be specialists in, and thus most comfortable teaching, epee, rather than sabre (or foil?).
Additionally, the club's equipment equipment stores might be best suited to epee (as it typically requires less equipment per fencer to get an epee-centric club up-and-running).
What are the coaches specialties, and those of the more experienced fencers in the club?
Perceptions/stereotypes: The coaches may be pushing you toward epee based on some common perceptions and stereotypes.
For example, those who are particularly tall and lanky are stereotypically thought to have a significant advantage in epee (more so than sabre or foil, it seems).
There are also stylistic considerations; due, in part, to not subject to the convention of priority, epee bouts tend to be slower and more deliberate than sabre or foil bouts (with sabre stereotypically considered the opposite). Thus, fencers who show a tendency toward that more careful, deliberate style are encouraged to practice epee, where it is most advantageous (or least disadvantageous, depending on how one looks at it).
How would you describe your build/proportions, and your fencing style?
As for the rules, the US Fencing Association (the sport's national) provides the documentation online
here.