Our new bub (almost 3 months) fell into the same night time routine as our other two (5 and almost 3) at about a month old. They always have dinner at 6 so bub goes into the bouncer next to me at the table, then all 3 have a bath together. Then while DH deals with the older 2, I get DS into his PJs & swaddle, breastfeed and asleep at 7. I never got the others into a bedtime routine until around 4-5 months but DS just fell into this routine naturally. We started by bathing him with the others whenever he was awake.