Margaritas & breastfeeding?

I'm going to a Mexican restaurant later and wanted a margarita. I have a bottle of breastmilk pumped already, and I thought if I fed her before I went, and then fed her the pumped milk later when she's hungry that it'll be okay? If I pump the milk after drinking, do I dump it or will the alcohol be gone from the milk after a certain time?? If anyone has any reliable sources, as well as opinions, that'd be great šŸ˜