What does "I used to date alot younger people" "like alot younger people" mean?

Im 14 f, and a friend 20 f were talking about dating after she broke up with her girlfriend, she was kinda venting and she told me that "she used to date younger people" "like alot younger people" i was confused and didnt know what this meant so i answered "as long as you dont do it anymore its fine" what did she mean by that? (The reason i dont know what she meant is because im autistic.)