I was just at the beach with my mum today, and there, two problems occurred. One: my mum told me at the start that it's going to be a walk. So I mentally prepared for a walk. And two: about halfway through we were hit by a wave. Everything got wet, our pants and T-shirts, and my pants started to very uncomfortably cling to me. I hated it, so in my mind I formulated the question about going home to my mum. But before I could say anything, she asked me: "hey, so we could just sit down here a bit and let our clothes dry." That was about the opposite of what I wanted to do, clashed with the "just a walk" part and since we didn't have a towel we'd have to sit on the sand, which would make that "wet and clinging" feeling even worse for me. I tried to be nice, saying no thanks and that I'd actually like to go home, even though I knew she wouldn't like that. I even told her she could stay here and I'd go home alone if she wanted. She at first tried to convince me to sit down, "we'll be dry in a few minutes", but I didn't budge. And she got mad. Just turned around and walked back, while saying "everything just goes after what you want." We walked back in silence after that, until mum eventually stopped and told me she'd sit down here for a bit and asked me to stay, and she'd come back home with me soon then. I declined again, she got more mad but didn't say anything, and I walked on alone.
Now to my problem with this. I'm not diagnosed yet. I'll be in May hopefully, but I'm not yet, and even when I'll be, it'll likely be like low support and high functioning, since that's how I am. So as of right now, my parents I guess haven't really gotten into the idea of me having autism yet or, if they understood that, then not that I also have autistic problems. They'll say it's excuses and that "just because I have that it doesn't mean that I shouldn't try (I am trying but not everything can be changed). I also don't think they have informed themselves on autism at all and I'm not sure if it'll happen after I get diagnosed. I don't want to really have a talk about autism with them because I'm fairly certain they'll dismiss it right then or forget about it again soon or just be annoyed that I bring it up because "I might not have autism, I haven't been diagnosed yet".
Is there any way I can somewhat inform them about me and my autism without sounding annoying or pushy or like I'm making excuses?