I have a girlfriend but I really like another girl more who should I choose?

You should really ask yourself two things: 1) why bother having a girlfriend? You may not be emotionally mature enough to know that liking someone it does not mean the two of you are right for each other; and 2) would you really want to be in a relationship with a girl who started with you after you dumped someone to be with her? That type of girl will eventually do something similar to you.
You need to be with someone who values commitment and will only be with one person no matter what.
If you are not sure you can handle that, then you should try being single for a while. That way you are not just clinging to one girl after the other and you will not be unfairly stringing girls along waiting to find something that “feels better”.

it depends which one is hotter