Many Internet businesses close down or have minimal staff working over the Xmas / New Year period.
Make sure you know how to contact your developer, hosting company and IT geek over the holiday period – you need to be sure that if your website or systems break, you know how to get them fixed as quickly as possible.
And don’t expect them to deal with any urgent late minute things you throw at them now. If publishing a new site, maybe wait until after the New Year. New sites always have issues, and when they do, some of these need fixing fast. For that you need people with time to apply to your problem.