Hi there,
And Welcome here,
Take a look at the Easy DMA and the FiFo tech in the IMU, that will allow full rate for sampling at any speed, also read up on the Filters. In the end you will need one.
Also take mind the BSP’s also need to be considered some work better than others as far as latency is concerned. Of course you’ll need to use interrupts as well.
We have several demo’s here that cover and some even have the code and compiler output so you can learn which and how it works. Check those and post up any questions you may have.
HTH
GL 
PJ 