Crossed wires

I was drinking in my local pub on Saturday with a couple of friends. After a few rounds, I usually offer to buy the barman/woman a drink. They are a good bunch, always serve me when it's busy and know what we drink so it's a kind of thank you for that really. And because I am a nice guy. There is a new girl working there and, being well into my journey of inebriation and starting to feel really happy, ordered the 3 pints of Fosters required by my friends and I. As she was serving I enquired 'Can I buy you a drink?' She said 'Ok, I finish my shift at 5:30, do you want to stay here or shall we go somewhere else'. I shat myself and spent the next 5 minutes trying to sort out the confusion. She got her drink in the end and I got out of what could have been an awkward situtation. I won't be offering to buy any barstaff a drink in future.