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

I want to negotiate but I am afraid they will withdraw. I am in Richmond, in case local advice matters. The hiring manager was friendly and open. Did it backfire?

If they say no, consider asking for something else, such as a review in six months.

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.