I can't talk to my girlfriend. When we're together she does all the talking. She's started to notice how little I talk since we started dating. I wanna be a good girlfriend to her. What do I do?

Start out by maybe writing down how you feel and tell her you just want to tell he somethings and to give you a chance to be transparent and express yourself. Keeping things bottled in won't end in a good result. Maybe go out and do something you both like to do enjoy a good time and ask to talk after just to get some things off of your chest. Try reading 5 love languages and getting to know each other better and that should help with communication and comprehension. You both have to find a way to communicate with each other without cutting the other off. I think this will help with some communication.