Me: Hey wanna hang out Saturday?

Her: I can’t, what about Sunday.?

Me: I’m busy Sunday, what about Monday at 7?

took a full day to answer Her: I can’t Monday, Tuesday maybe.

no reply from me for a few hours

Her: Wait maybe I can do Monday.

Me: Ok see you then.

My last reply is what bothers me. Was I right to not next her? I know for a fact that she’s free Monday. Only reason she’d say no would be because she’s doing “something better”. Maybe Chad cancelled on her. And I don’t know how to deal with “maybe”. Was I right to assume it’s a yes in this case?