AITA for not wanting an adopted brother.

EDIT: I (18f) am an only child of my parents. Just an hour ago they asked me if I would be okay with the idea of them adopting a child.. My parents are always fond of kids but after my mom had me she had miscarriages and later on she got uterine issues. When I was small I always wanted siblings so bad. My birthday wishes used to be to have a sibling. Now tht I’m older the need to have a sibling is gone yk I love my family the way it is. Past few months my mum has been bringing up how I might feel lonely later on tht all my cousins have siblings I don’t and stated “siblings are siblings they are their own”. Well I’m totally okay with being alone maybe I might have a family of my own in near future or if not that’s fine I’ll live my life as much as I can. So back to the adoption baby he’s just 15 days old. His biological mother died during child birth and his biological father doesn’t want to take the baby so he’s left all alone none of the paternal maternal side of the family wanting to take him too. My parents heard abt this and wants to adopt him. Well when they told me I went blank and cried. Is this something they actually want to? Like actually? Cuz truly from me it was a no. I really couldn’t say anything but breakdown in tears. They obviously took tht as a no. A lot of emotions just dwelled up and released. They let me be and said it’s fine but I feel guilty what if they actually want want to adopt the baby and I ruined it. But at the same time selfish to say this but I’m going college this year and I have a lot on my plate going on. I work and provide for my family rn my dad lost his job my mum works but not enough to cover full expenses and I am also saving up for my college tuition fees too. A new baby brother is not on my addition. But I don’t want to overlook my parents feelings and choice though idk what I should do or say

EDIT: honestly it’s leaning towards me problem idk. I come from where people consider single only child daughters are useless. And grands didn’t acknowledge me as a grand child because I was a girl. And now thinking tht I’m gon have a new adopted baby brother made me think of how he’s gonna be so loved and appreciated. Now I feel more of a shit hole to think smthn like this