When she says “I’ll let you know”

I went on a date with a girl and asked her out on a second date, she hit me with the classic “I’ll let you know.” Naturally, I left it at that and didn’t text her anymore. Fast forward 3 weeks later and she texts me “If I still want to get together.” I’m reluctant to go out again because I don’t have time to be a backup option.

Is this the wrong mindset?

UPDATE: I messaged her back last week and went on a date this Friday. Ended up with us sleeping together. What happens next we’ll see, but I guess putting pride and ego aside can be beneficial as long as you have no expectations.