Having this baby (and others to come) will change your life in many good ways (complete adoration of another human being) and some not-so-good ways (crippling anxiety and depression).
Despite the massive amounts of information you consumed prior to birthing your daughter, you will have no idea what you are doing. There are many wise people surrounding you who understand the difficulty of parenting, let them help you.
Sleep books will promise a lie - that they can train your baby to sleep through the night for life. Your baby will sleep, then not sleep, then really not sleep, then kind of sleep again, and finally sleep through the night, only to repeat the cycle when she teethes, gets sick, when you are in a different place or move, when another sibling arrives, and so on and so forth. Her bedtime routine will change over and over again. You will want to pull your hair out wondering what you are doing wrong. But, you are doing nothing wrong. As one very wise person once stated, all kids' phases - good and bad - pass. Don't fret about it.
Go with the flow in parenting. Let your kids be kids. You will have a great time watching them develop motor skills, language, social skills, and many other things. Learn to laugh rather than feel frustrated at the messes they create. Messes are just a sign of children being children. Be adventurous. Be relaxed. As much as you can, enjoy this time with them.
If you don't enjoy the time with them, don't feel stressed about it. Some things are not enjoyable - poop messes, tantrums, colic, etc. That's okay.
You are doing great. Even when you feel like a absolute failure. Even when you stay awake at night analyzing everything you said and kicking yourself for doing/saying something wrong and curse yourself for bringing your children to such an imperfect mom - you are doing great.
Your children will love you. They will forgive you. They will learn with you. You will teach them to be kind, compassionate, respectful children and they, in turn, will teach you patience, understanding, and how to love unconditionally.
As much as some things get easier, some things get more difficult. Your children will go from being absolutely dependent on you, to screaming for their own independence. They will have their own thoughts about everything and will make sure to express these to you at very inconvenient moments.
Sometimes you will cry. Sometimes you will feel so frustrated that you have to either remove them from the situation or yourself so you can both regroup. This is parenting.
Don't let outside observations or comments get to you. Remember that even those who seem to have perfect and easy children still struggle with various things. And don't take parenting books and websites too seriously. Use pieces of advice that would suit you best and let everything else go.
Above all, let love guide you. And drink copious amounts of caffeine. You'll need it.