To get involved in showing I would work with your breeder. Does your breeder currently show her dogs? If so, its a great way to learn. If not, become involved in your local kennel club (all breed) as well as your boxer clubs.
Also by working with such clubs they can critique and evaluate your bitch. You may think she has everything perfect to standard, but not even the best boxers winning do, so its best to have her evaluated by a pro, or handler, and find out her strong points and her weakness. Do you want to handle her yourself? I know many local kennel clubs hold handler classes and its a great way to learn how to hand her. Also will get you familar with the ring and offer great practice.
There was a point where people think flashy was the only way to go in the ring. However IMO flashy is nice, but too much flash can take away from a lot of great points like the nose length. Plains are doing just as good as flashy in the ring. I would never tell anyone not to show due to color esp if the boxer is a great example of the standard. Color mean nothing outside of fawn and brindle.
Its been told to me that males are easier to finish. Reason being is there are more entries of bitches in the ring, therfore making majors hard to achieve. There is an entire point system by the AKC that require a certain number of dogs to be entered to get a certain number of majors. Its all locations too - Jennifer Newcastle has that info.
My honest opinion is work with your breeder. If they are not willing to work with you and are not currently showing, then I would looking into the boxer club or kennel club. If you want to do it , then do it regardless of what anyone tells you until you have you dog evaluated. If she gets evaluated and is not to be the best fit to the standard, dont let it stop you from being involved. I go to boxer shows, meet breeders, attend seminars, read books and I have no show prospect! Tee hee. However for the day I get one, I will be prepared.
So thats my opinion!!