Labour of love - children give deep meaning to your life, but you must embrace that to succeed
Once you become a parent you have to learn to love and embrace the work of parenting and (sometimes) the struggle. You have to love your children. Appreciate that everything children do is from curiosity and learning and requesting help with their basic needs.
You have to come to terms with the fact that it's not about you anymore. That life has more purpose than just you. Your life will end and theirs will be a continuation of yours, in some form. It's increasingly about their future and less about yours. It is impossible to be a successful parent and be self-centered. But if you can embrace the sacrifice and responsibilities joyfully, you will be rewarded beyond measure with their joy, perspectives and companionship.
One final note remember, that everything you say to your child, becomes their inner voice.