So I'm gonna add some details, the trip to Japan is really important to me, as it is a replacement for a trip to UK that I won via an essay and video making competition around 4 years ago and never got to go because of scheduling reasons and then later covid. The trip is all paid for and I get to choose to go anywhere I want for 10 days! It is like a dream for my autism, I chose all the cool museums and places related to my special interests.

The organizer (person who hosted the competition) the suggested that I could let this girl, who won a different contest and got a different prize with the organization go with me because I have space for another person in my room and the girl is very open to new experiences. Plus the organizer said we have a lot in common, how we're determined and how we both got hospitalized from school stress. I don't want this at all. I'm always happy to make new friends, but to let one person I barely know go on such an important trip with me is different.

I told the organizer I can try to talk to the girl to see if we'd click and get along well, and if we do I'm fine with her going. And I did actually talk to her, and she's alright, but she's too different from me. I don't think I'm gonna have fun on the trip because she probably won't understand and will question my choices about the places I chose to go. I also don't want to make accommodations when it's a trip that's supposed to be for me. I don't want to mask because this trip is like the ultimate autism stimulation for me. I don't want to make the girl uncomfortable by stimming visibly and I don't want to mask and feel uncomfortable myself.

I'm already not going alone, as the organizer and her boyfriend will be there to make sure I'm safe and etc. And also pay for things. Just that they have no say in what I choose to do, and they sleep in a seperate room from me.

I don't want the girl on the trip with me for all the reasons above. And especially the fact that I will have to share my room with her because after a long day I really need space and privacy for myself. It's different when I share a room with family members.

I told the organizer today that I have made the decision to go on the trip with just myself and she said it's okay but she sounded quite disappointed and now the girl will be too because I'm not letting her go.

Am I selfish for this decision or is it justified?

eta : To clarify, the organizer isn't inviting the girl to cut costs for her own prize. She was a winner of a start up competition and has already received the investment money which is her prize. The organizer happened to mention going to japan to her and she was like "lol can i go too" and because she's really friendly she told the girl something like "actually maybe we'll see first."

also I made a reply to a comment about how the trip works incase anyone else finds this whole thing weird which I totally understand.