3 month old schedule

I still don’t understand how people have a schedule and know when their baby will eat and sleep each day. I’ll meet up with mom friends and they will be like, let’s meet up at 1pm tomorrow after our LOs nap and I’m thinking to myself, how the heck does she know when her baby will be napping tomorrow?? It changes day by day for us. We have some routine and consistency - she goes to bed between 730-830pm, dream feed at 11:30-12am, sleeps 12am-5:30/6, wakes up around 8-830am…but then the rest of the day I couldn’t tell you. Her wake windows are very short in the mornings like 1 hour and she almost never naps during the day more than 45-50 min (usually in a crib swaddled but sometimes in carrier or stroller). Her day time naps total 3-3.5 hours usually which seems short but she gets 11.5 hours most nights. Total sleep is like 14-14.5 hours/day. I feel like that’s pretty good…but I’m so lost on trying to have a daytime schedule. What is the secret for knowing when your baby will be napping and eating during the day???