Which terminal do I go to!!!?? Please help~ (O'Hare Airport)?

I'm 13 and in 3days I'll be flying from Chicago, IL to Orlando, FL. BUT I dunno what terminal I go to! First time going around an airport by myself. I've flown alone many times but usually my parents or an escort take me to the gate. I got my ticket off of Expedia.com and I have my Conformation code, ticket #, and itinerary # but I don't know what terminal to go to!! I'm using American Airlines and going through O'Hare Airport. Help please! And any extra advice about getting around (O'hare or MCO)will be greatly appreciated! Thanks~