Donate Your Boat to Charity

My girlfriend invited me to dinner at her yacht club, and someone at the table asked her to race on his boat with him, but she was already committed to another sailboat. So he asked me, and I accepted. She said I shouldn’t have accepted because I was just her guest and I shouldn’t have agreed to get involved in anything at her yacht club independent of her. I saw it as a chance to improve my sailing skills, and I felt she should be happy for me to get this opportunity. This is a boat she’s always wanted to sail on, so maybe she was just ticked that I was available to get this opportunity and she wasn’t. If so, isn’t that selfish and controlling? She insisted that I back out of the race and sit at home instead. She wants this part of her life exclusively to herself and only includes me selectively. She accuses me of just copying her interest and doesn’t consider that I have a geniune interest in this on my own. What is this really all about?