My DD is 4months too. We have had a bedtime routine since birth, and now just getting a daytime one together. Like PP said some days it doesn’t go to plan, it will change, but it’s more about the motions than the set times.
7.30 (approx) wake this is my base point for the day.
She will then feed every 3 hours from whatever time her first bottle is, up until bedtime. (8.00,11.00,15.00,18.00)
First nap is 1.5hours after wake (around 9.00 I get up for the day whilst she has this). Not yet established long naps, but we have made progress from 20-30 minutes, to 40minutes at the minute. Then I have 1.45-2.0hour wake window from when she woke from that nap.
Usually 4 naps per day. 2/3 done at home using a short version of bedtime routine. 1 nap in the pram on a long walk. Last nap ends just before 6pm bottle.
Bedtime 7:30 start with a bath, pjs, bedtime feed upstairs, and then put down at 8.15, until the morning. Gradually going to get this a bit earlier.