Why is my non-inverting band-pass filter not working properly?
You can't design a bandpass filter that narrow with first order sections.

When you take the peak response at 20/25 kHz, and then find the frequencies at which the response is 3dB down on that, that will tell you what this filter is doing, but it won't get you to your target specification.

The problem with that is that with only first order filters, and a narrow passband, the peak will be suppressed by the combination of the passband loss due to the very gentle transition bands. 

You can check this by modifying your circuit to have just one, or the other, filter element in circuit. You'll then find the -3dB frequencies come out as you calculated. Then check the amplitude response at the other frequency, and you'll find it's still around 1dB low. Those two lows up to suppress your peak from the expected +6dB.

A bandpass filter that narrow requires higher order sections, with steeper transition bands.