I've had long chats with a number of moms over the years who try to schedule naps and bedtimes. It appears, from long observation, that some littles take to scheduling very, very well. Most can be nudged in the direction of a dependable routine, but it doesn't really 'take' until they are several months old. And Some Babies Do Not Schedule. Ever. Or at least until they are well into toddlerhood. They can not help this – they are pushed and pulled by irrestistable inner tides, well beyond their own control. These are sometimes called High Needs Babies.
If you're mothering one of the Non-Schedulers, and have in your mind that you 'should' be able to get her into a dependable routine, you will feel frustrated, perhaps even see yourself as a failure. You're not a failure, unless you persist in trying to make the impossible happen.
The moms I've known who do the best with it don't think that way. They realize that this baby is simply requiring them to be more flexible. Many of them make peace with it, and begin to discover the joys of spontaneous, in-the-moment living, and the ways that approach can actually be filled with fun and discovery. They must, of necessity, learn to observe and 'read' their baby's signals, which can result in enhanced closeness as the baby grows older.
Seem from that direction, it can be a gift. Every option comes with trade-offs, and when we recognize that, we can make the most of the silver linings.
Wishing you well!