Congrats to you:) You were in an awfully tight spot and you are in the right to fight! Just remember, these attorneys are there to make a buck off your ex. Do not feel intimidated...this is what attorneys do for a living. Most people who become lawyers are egotistical, so think of it that way. Think of yourself as your child's advocate and messenger. You are the warrior. If you do have to represent yourself, do the best you can to stand up for yourself. Be organized with your documents, be polite and dress in business attire, don't speak out of line unless instructed to by the judge, make sure you give the judge a copy of everything you have if he asks for it, and be honest. Don't try to pull a fast one over on the judge either. If you come across as honest and civilized, you'll do just fine.
Best of luck:)