looking for answers

A child can "ask" anything they want, but it is completely and totally up to the child's parents whether they will go along with what is asked and permit it, or whether they won't. Yes, there are people who will adopt a 14 year old, but they are few and far between. The process can take anywhere from a few days to several years, depending on how long it takes to find a family and whether that family has completed the steps for getting approved already, or whether they haven't yet.

so if the child's parents says no the child can't go up for adoption no matter what? even if a social services worker comes?

If a social services worker comes to your home, it is probably to investigate claims that a child is being abused or neglected. IF those claims are true and the parents show no interest in changing, the child can be removed and placed in foster care. But the parents would still have to agree in order for the child to be adopted by someone else. It is possible, if the parents continue to be abusive to the child, for a judge to put them on a timeline for improving, and if they didn't improve, then the judge could remove their rights against their will. But that process takes several years. IF the claims the social worker is investigating are false, the child will not be removed, and the parents would have to agree for the child to be adopted by someone else.

I don't know what is happening in your family that makes you want to be adopted by someone else but is there anyone you feel you could talk to about your family situation? A teacher, school counselor, coach, outreach officer, youth minister, etc. If you are being harmed in any way, you need to report this to a trusted adult and if you don't get the help you need, you report to another adult and keep reporting under you get the help you need.