wanting to cancel family trip

hello recently my family had told me that they were going to buy my family a plane ticket and a four day hotel stay at Nassau Bahamas, the problem is i don't want to go, i have been focusing on wanting to save money and work and stick to my own plans for that month coming, it falls in the month i wanted to start my life and move out but instead i come home to my family wanting to go to a vacation, i wasn't exactly happy about it obviously because i have my own plans and in that same month this came out of no where, they hadn't talked about it once not once besides that same day i asked them why they wouldn't change it another month or wait till next year so i can pay for my own instead they've already paid for the plane, hotel, everything needed, i told them ig if they want to buy my way now mind you im not normally as ungrateful as i sound in this im a very thankful person but this is different, i said okay but i don't want it and to be honest i don't feel i will enjoy it as much as i would till next year it came out of no where and i don't want to go if feel i wont enjoy it as much or have as much fun, ive been focusing on my life and wanting to get it together and yes i know life is all about spending time in the moment but life also has to continue or time will get ahead of you, I'm 20 and living at home still and you know that conflict where you love your family but there driving you crazy because you want your independence, im not sure if i should tell them i don't want to go or cancel their all talking about it and already bout so many things for it but truly i don't want to go and feel guilty what do i do? TL;DR