I wish my baby brother was never born
Why would you say something like that about your brother?
Had it not been for him I could have had my mom all to myself
You shouldn't feel that way towards your brother. Just because your mom needs to spend more time taking care of him than you. It doesn't give you the right to say things like that about a baby.
He's been the center of my mom's attention since he was born and I realized it just recently.
You should consider how much more help he requires right now since he's a baby. He won't need so much of your mom's attention forever. Once he's bigger I'm sure you'll love having him around to play with.