Is mixing drinks actually dangerous?

Hello!! My mum always tells me that I’m more likely to be sick if I mix drinks. I’m not sure if this is true? So I’m 18F with emetophobia, so I’m always very careful with my drinking, but my friend is coming over on Friday and I’ve got Kopparbergs and vodka. I wanna do vodka shots (because duh it’s FUNNNN) but I don’t wanna be stuck to just pure vodka all night, so I wanna drink 4-5 bottles of Kopparberg too like I normally do to get wasted.

BUT I’m not sure if this is more likely to make me puke? I know none of you can say for sure but I’m just not sure if what my mum says is a myth and if it’s actually based on volume than mixing?

I nearly puked one night but I had Kopparbergs, vodkas, and three sourz shots. I think the sourz is what did it, but not sure.

Obviously I’m gonna make my own decisions and I’m not relying on this sub lmao, I’m just wondering!!:)