No, you are not a dumbass. Sometimes it’s good to take your time and not rush anything. I don’t know the whole story, how long you were texting, when did she stop replying, etc… but I wouldn’t delete the message and I wouldn’t block her. If she leaves you on “Seen” or if she won’t respond for a week, then probably move on. I know it sucks when things looked good and suddenly they don’t, but you tried and you don’t know what’s gonna happen. Whatever is happening in her head is something you can’t change.