By the way, OP, I saw you said you read the Gina Ford book....I made the mistake of doing this when I was pregnant as well. One of the things she gets really wrong is her theory of babies' naps. She says something ridiculous like "....and then you put your baby down for a 2 hour nap in the early afternoon".
This really screwed with my head, because for the first 7 months of his life, my DS would not sleep for longer than 35 minutes at any time of the day (thankfully, he slept a little longer in the night!). I got myself into a right old state thinking that I was 'getting it wrong' and 'failing' to get my little boy to have the 'proper' long daytime nap that he needed.
After about 5 months of torturing myslef about this, getting really upset and generally losing my marbles (!), a good Health Visitor gave me a good talking to, where she explained that Gina Ford is full of shit a large proportion of babies takes lots of little naps throughout the day, at different times each day. And that a more predictable 'nap routine' is quite unusual among young babies. She suggested that if I just wait and watch DS's cues, he would probably naturally fall into a more set pattern, and take longer naps, around the 7-8 month mark. And lo and behold, he did!
Now he is nearly 9 months old and he has a 45 minute nap at 9am and a 90 minute nap after lunch - exactly what Gina suggests! But I have done nothing to make this happen....DS just gradually started staying awake longer in between naps, and napping for longer periods of time around 7 months old.
So PLEASE don't get stressed about your LO's daytime sleep patterns. A good rule I followed for the first 6 months was: DS will probably need a nap 90 mins/2 hours after he last woke up from a nap. So I watched him for tired signs (staring into the distance, rubbing eyes once he had control of his hands, yawning) from around the 1hr20 mark, and would then rock him to sleep, go for a buggy walk, or a drive, or swaddle him and give him his dummy in his Moses basket once he was about 12 weeks old and hope he would drift off.
Once I realised that frequent catnaps at different times of day was NORMAL for the first 6-7 months I chilled out immensely. Stressing about his nap times really ruined the first 3 months of my little boy's life for me though, so please burn that sodding book, and once these craze first few weeks are over, just watch for your little girl's cues and let her sleep when/where she wants during the day.