Offer arrived, can I still ask for more? (Cleveland)

I want to negotiate but I am afraid they will withdraw. This is my first time dealing with any of this. The benefits are decent. 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 7 months ago, and it got easier once I kept a simple log of every call and form.