I'm a software developer with 4 years experience. I'm in the USA. I had a final round of interview with hiring managers at my dream company. We had a few good laughs and I seem to have most or all skills they are looking for for the position. They said they could see I will be productive from Day 1. We discussed the salary range and my earliest start date. Overall, I feel like it went pretty well. They have 1000+ employees and a large IT department. Let's call them Company A.
The Company A knew I had another offer from the beginning of the interview process, and they have tried to speed up the process for me. Today was the last date I could delay my answer for the offer with Company B. Company A knew about this, and told me they will try to make decision by today.
Unfortunately I did not hear from them by the end of the day. I really wanted to work with Company A, so I rescinded the offer from Company B. It was a hard choice. But whether this is the right choice or not is not the focus of this question.
I plan to send a follow-up email or call to the HR contact tomorrow morning. Given the above context that they knew of this offer, and every staff from Company A who I have spoke with seemed very personable and professional, I want to ask your advice whether I should mention I rescinded the other offer. My feeling is that they might like me more, or I could look desperate. Should I mention it? Would it hurt if I mention? If I should, please suggest exact wording I could use.