Negotiating an offer, is it too late? - 7 weeks in

I received an offer as an accounts payable clerk and I think the pay is a little low. I have read a lot of threads here and could not find my exact situation. I have a competing interview next week. Did you negotiate?

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

I thanked them and said I was excited but hoped we could talk about the pay. They came back with a bit more.