Before I say anything, I should say that there is no substitute for advice from a GP / Doctor. They are best placed to know exactly how plane travel will affect epilepsy.
That aside... I dont see any reason why epileptics shouldnt travel on an aeroplane like any other person. I would consider what your triggers are (if changes in air pressure are a trigger for you then I would perhaps advise against air travel) and how air travle is likely to affect you. If you were to apply the logic from your problem: (A) You shouldnt drive incase you have a sz in the car, (B) You shouldnt work with any machinery incase you have a sz, (C) You shouldnt drink any alcohol as they can interact with meds and cause a sz, (D) You shouldnt go to clubs as the lights may cause a sz... the list is endless.
Assuming there is no immediate problems that you can foresee, I think you will be ok. Try talking to your mum as well and have a discussion about her worries. It might be that you can talk this through and resolve her anxiety about you flying.