I've finished a middle grade book and have done a couple of rounds of edits on it. I'm almost at the point of submitting it to agents. I've got one big reservation though, and that's all the agencies I've looked at specify 1st 3 chapters to be sent. In my book the real action doesn't begin u til chapter 4. The idea is it's the first book in a series so there's a fair bit of scene setting required.
I guess my question is, am I better to rewrite to get to the action faster, or explain in the synopsis and cover letter? I'm assuming ignoring the rules and subbing 4 chapters would be bad form? Any advice very welcome, I'm totally new to this. Should also say I've had feedback from target age middle grade readers and they didn't say it was too slow to get going, I think the writing is quite pacy it just doesn't get to main events til ch4.