my girlfrined(19f) and i(19m) have been having problems lately because she thinks i dont understand her. i think i understand her but idk what im doing incorrectly. how do i get better at it?

we've been together for 9 months now and there have been some major fights and things that have happened to us because of me. ive always communicated with her and explained her properly about my side and she appreciates and gets it. but then when she explains things i feel like i understand them and get her but she thinks i dont. later she gets upset about this and the whole thing kind of repeats. i try all the time to resolve an issue as early as possible giving her enough time and listening to her problems and also explaining my side of the story and my opinions but then she gets mad that she understands what im telling her and i dont what shes telling me. i think im good at my speaking skills and good explainer idk if thats the word but yeah and she kind of doesnt do it as well as me so ig i dont get her even though i feel like i do. please help me out with this as i really care about her and us and i want things to go smoothly between us.