Is it a good idea to drink for the first time in this scenario

I am a 16-year-old guy with ADHD heading to a Halloween house party, and I’m thinking about having my very first drink—maybe a shandy or a vodka Sprite. An older brother figure warned me against it, saying that between my ADHD and my complicated, unaddressed crush (who is my costume partner for the night), I’m highly likely to lose control, overdrink, or do something stupid. I want a brutally honest answer: Is there really that much risk if I stick strictly to just one single drink, or should I still hold off entirely?