I want my parents to leave my aunt (40s) and her 3 kids (5 8 and 17) behind
Do you want them not to go with you guys?
I want my parents all to myself.
It would be great if you got to spend more time with your parents but it is not good to abandon your aunt and her children. They will be upset and it will cause fights within the family for a long time.
We are not even blood related.
Still you refer to her as your aunt so you are family. If you really feel you want to be with your parents alone talk to them about it? I think they might be understanding and make special time for you.