It's so amazing and admirable that you intend to put yourself last in order to be the best mom you can be, helping your child with everything, doing all the little things that you think matter in the moment so that someday on Mother's Day you receive a card from your little one about how you were always there and baking cookies and volunteering your time and not resting while the baby rested so you could DO IT ALL... Yes, wonderful. However, it's not reality.
It's just like that old airplane reminder of putting on your own air mask before putting on other people's. You cannot help anyone or be a great person or mother to your kids if you aren't first taking care of yourself.
You are going to see that in the first year of your baby's life it's all up to you to do everything, to feed them, clothe them, clean up after them. They rely on you significantly. And because you are MOM they rely on you even more so than they rely on dad. It's just how it goes. And you are willing to do those things to be a great mom, which is awesome.
My caution to you is to not get so involved in being a good mom that you totally forget about who you are. It took me a year to learn this lesson. After my son turned one is when I realized, "Hey, wait a minute! I still exist here, outside of my role as MOM! What about me?!" I started running and getting myself back in shape. I started going to the library to get books for me to listen to while I drove in the car instead of listening to baby music. I decided that it was ok for me to get a babysitter for a few hours so I could go get a hair cut for the first time in a year.
When your baby comes home from the hospital is definitely not the time to read this post. You are going to want to protect that baby from everything and you will be so in awe that you made this creature that you will want to be near her or him every waking moment. That's ok. I just hope that you reach a point some time in that first year where you stop and realize you can't do it all very well if you don't first take care of yourself. Your baby will be just fine without you for a little bit here and there. I promise!