You've posted two questions on the same day about your three-month old. I'd consider getting a good book on infant development, one that includes sections on newborn-to-year-old children--ask your pediatrician for a recommendation, but please, don't seek out books that are all about "Get your baby on a schedule immediately and sleep train and feed train and make baby live by your desired schedule." One reply to the other question really nailed it -- it can go downhill fast if you listen to the authors who claim young infants can adhere to an adult clock.
At three months, he is still a very young infant; he doesn't need to be scheduled by an adult but the adults should follow his lead and let him sleep when he's sleepy and roll when he's ready. Give him as much "tummy time" as the pediatrician recommends and don't push it beyond that, and don't expect that if he rolled a few times earlier he's going to keep doing it or else he's not developing -- there are many, many stops and starts to how a child develops.
Try to find a group where moms of new infants get together with each other and their babies. I was in a group like that when my daughter was born -- the local hospital organized it, and we sat around with our young babies on blankets on the floor, and a pediatric nurse took our questions and we all just casually chatted. It did a LOT to help us all calm down and not get fixated on schedules, "milestones," "Should baby be doing X by now," and so forth. Really a big help! Check your local hospital or hospital chain--they mostly all have education departments or new parent liaisons who can help, even if you did not have your child at that hospital.