Will you need a count in?

Removing the stuff you don’t need is easy enough, but you might need a little count in. If you have a recording with a decent count in (at the correct tempo, or you might need to experiment with your audio editor’s tempo editor), try selecting the region and doing a bit of copy/paste into your shortened track, and slide it around until it feels okay. Set its volume to taste and then export the entire file as a new audio file.

Bit of extra work, but better than missing the start!