Adjustment of Status - I-485

Hi guys, thanks for all the input. They really help. After our interview the IO gave us an RFE to submit a birth certificate of our daughter. We submitted it 2 weeks after the deadline. My wife(us citizen) wrote a letter explaining why we couldn't meet the deadline. We added a letter from vital records showing processing times. 3 days later we received an approved i-130 letter. Our i-130 was approved. A few days later we got another RFE to submit new medicals since the last one expired. I submitted the new medicals on 9th January. I've seen a few people talk about i-130 being approved and waiting on a decision for i-485. If your medicals all came out negative (which mine did), are you always guaranteed approval? And how long will it take to make a decision? When can I make an info pass if I still haven't heard from them. Any advise or experience. Let me know