I found that though I am a sub I can be masochistic and sadist, so I will enjoy the sadist side of BDSM, therefore I can be a switch in some ways to be able to exert the sadist part of me by becoming a Dom.

You just need to talk things through with your Dom, decide on whether she would want to have a relationship being a Dom or sub, then choose what to do about it. Tell a night when you might want to be dominant and her submissive. Then vice versa. Whatever works for you really in the time scale, then decide on that, change it as you wish. You decide on an hour for you to be dominant, then in the next hour submissive, that way you will aviod the confusuion of you both trying to be Doms or subs.