Ok, so I need some major help?

Ok, so I've been going out with this girl for about a month so far, and tonight I asked her to be my girlfriend, and she said that we should wait a little longer to take that step. Which personally makes me believe that she is just using me for other stuff. So would it be considered cheating if I were to start dating this other girl aswell, because it does seem to me that she is not interested in making a relationship, like should the girl I have been dating just become a FWB?