You need to get to know some breeders. They don't have to be Chihuahua breeders, but it really helps to have a mentor to help you at the beginning. I got involved in showing when I was 14, because I had a Saturday job in a pet shop and the owners bred German Shepherds. Showing is a very expensive hobby, and requires a lot of travelling. which is why it is good to go along with someone else and get acquainted with the process and the people before you start looking for your own dog.