Negotiating an offer, is it too late? - any advice?

It is the first offer in 5 months and I do not want to mess it up. I have been trying to stay organised about it. The benefits are decent. Did you negotiate?

Most employers expect a short conversation. Mine did not even blink.

Thanks for writing this out. I went through something close to it 5 months ago, and it got easier once I kept a simple log of every call and form.