Is 18 months too young to drink caffeine?

Okay first let me just say I DO NOT let my 18 month old daughter drink caffeine. I do not think she’s old enough at all, which is why I’m frustrated. Once a week, my husbands grandmother has a family dinner. My husband has a very small family, he has one uncle and that’s it. So its me, my husband, our 2 daughters, my mother in law, my husbands uncle & his wife and my husbands grandparents. Well, my in laws give my 18 month old sips of their pop which has caffeine in it. Sometimes my husbands grandmother will even give them sips of her coffee. I love my in laws so much, we all get along. I love them almost more than my own family. My mother in law doesnt give my daughter caffeine but the uncle does and the grand mother. I love them dearly but they think it’s funny, even when I tell them not to. I tell them she’s too young and that it keeps her up all night. Which is true because one time she was seriously up until 4 am. They just laugh & say “what else do you have to do?” Because I’m a stay at home mom so I don’t work. But I do baby sit & im a full time college student. So I get up at 8 am sometimes earlier to begin my day. And the u clue said tonight “did she stay up all night last week? I was giving her a lot of sips last week when you weren’t looking and you never even knew it”. It honestly bothers me too that she is drinking after them, especially with this COVID19 stuff.

Anyway, am I being over dramatic? Should I just let it go since it’s only a few sips of caffeine? Maybe I’m being a crazy helicopter mom. My husband hates confrontation so I definitely don’t expect him to say anything but he understands my frustration.