Most Helpful Girl
We women like to overthink. She's probably thinking you're not attracted to her now. It's not wrong at all for saying no.
Message her, and tell her you're sorry for turning her down. You think she's so sexy, but you just don't want to have sex yet. Say you hope she didn't take it the wrong way because you enjoy seeing her, and tell her again that she's super sexy. She will most likely fall in love with you and then you'll get married and live happily ever after. Well, maybe not all that, but she'll really like you a lot more.
Most Helpful Guy
Well if you weren't ready, then you weren't ready. Especially if you had no condoms at your disposal.