smackie9 might be correct on this. The other thing is that most girls sense desperation and do not like it. When you asked her if she was serious about dating you later, she probably took that as a red flag because it seems desperate.
The best thing you could do right now is just act friendly and not bring up dating with her for a long while. Just hang out, talk casually, and enjoy her company. Don't push for anything more or chances are there will never be anything more.
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