I think like other people have said it is up to you how strict you want to be about routine. But also some babies will take to a routine very easily whereas others will not take to it so easily.
I started a bedtime routine with Thomas about two weeks ago but we don't have a fixed time for bedtime because it depends on how his daytime naps and awake times have gone. Sometime between 7.30 p.m. and 9.30 p.m. generally. Our routine is a good feed, a bit of playtime, then a bath, then another quiet feed in a dim room, lullaby, and then I generally have to walk round the room with him on my shoulder for ages, LOL, that is not supposed to be part of the routine but he is often very uncomfortable with wind in the evenings. However it does generally work as I think he knows it's time for his long sleep afterwards, he is still generally waking every three hours for feeds but at nighttime he will go straight back to sleep after eating whereas during the day he will stay up and play.
Over the last few weeks I have been keeping track of his naptimes during the day to see if there is any pattern, they are still fairly random, but he normally has about an hour and a half nap in the morning, then a longer nap at about midday, maybe two hours or even a little bit more (this is normally when I bring him out in the pram), then another one or two short naps of forty-five minutes to an hour in the afternoon. But there are no fixed times for this and sometimes he wants to do something completely different or has a really sleepy day and I just go with the flow in that case. I do try to keep him awake for at least an hour and a half or even two hours during the day, but it doesn't always work.