Quoting PooterButt'sMommy:" regardless of age. when i got pregnant, i thought, "well, i practically helped raise DH's cousin's kids. ... [snip!] ... was like 6-9 months when i started watching her. i didn't realize that younger is MUCH more difficult. newborns are harder."
Smurf, my son had me fooled, he was the perfect newb. Thought my daughter would be the same... nope! Pretty sure she has colic and she is just.... a real baby. A slap in the face to the little fantasy I was living in when I had my son!
OP being a mother at any age is hard, but it is completely different than being around kids or baby sitting or whatever you are considering "raising" your siblings. I used to think oh, I've been arounds kids of all ages my entire life, I got this. Then reality hit me and it hit me hard. It is so hard being a mom in every aspect. Some people might say it's easy, hell I know I have, but it's hard for everyone. There is so much that comes a long with being a parent that I'm sure you don't want to give up just yet.
Small things like showering alone, peeing alone, eating a hot meal, not smelling like spit up, showering every day, going out with friends whenever you feel like it, etc. You wont be able to do that with a baby... Hell it's been two years and I still can't pee alone.