Babies haven't the book
Nope. The baby hasn't read Gina Ford or Tracey Hogg.
It also hasn't read any of the books on baby wearing or attachment parenting.
Listen to your instincts
If you've never had any real experience with babies then.... um, what instincts?
At 3 weeks post birth, if she's reaching for a guide book and attempting a routine then the odds are she's struggling and she isn't happy with just whinging it. A little support from people close to her wouldn't go amiss.
Some babies genuinely prefer to have some structure and routine. Some don't like waiting until they realise they are absolutely starving or so tired they just scream, some prefer to have food offered or be encouraged to sleep regularly.
Slavishly sticking to a routine or parenting style that makes you or your baby unhappy is not the best idea, which can be the real and practical problem with some of the tighter routines such as GF. But equally, sticking to a baby-led or attachment parenting structure when your baby is clearly unhappy with it is not the best idea either.
I could have read every book about co-sleeping, attachment parenting and baby-led feeding and been adamant that was what I wanted to do, but that wasn't what my particular baby wanted to do.