First. You don’t hint you want to be exclusive. You tell/ask directly. Hinting is just idiotic and people always miss hints or think it’s something else. So if you want to ask her to actually be your gf, ask. Worst she says is no.

Second. Of course they can. Women and men have been friends since forever. You thinking that more is happening is because of your past and not because of her. You are creating an issue because of being hurt. It isn’t a red flag she has guy friends. Plus she told you and didn’t hide the encounter. She is showing you that she can be trusted. But if you can’t trust her, don’t ask her to be exclusive with you or even be with her. She doesn’t need to be judged or second guessed or controlled for having friends of the opposite sex.