Negotiating an offer, is it too late?

It is the first offer in 10 months and I do not want to mess it up. I have read a lot of threads here and could not find my exact situation. The hiring manager was friendly and open. Did it backfire?

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.

Ask about the range, not a number on its own. It felt more collaborative.