When to have a baby shower?

RR • Together since 2009 | Married since 2014 | 3 M/C`s | MTHFR | Rainbow baby born 07/02/17💗 #2 Due 12/21/20!!
I'm only 18 weeks along however my family lives in Eastern Europe and the U.K. So we're trying to give them a heads up for the baby shower so if they want to come they can find good deals on flights etc... plus plan a vacation if they decide to explore the states. Or figure out if they would rather wait till baby gets here. So we originally thought when I hit 36 weeks would be a good time for a baby shower but a friend of mine said I should do it earlier just in case baby gets here early and also so that I can enjoy it rather than be super pregnant and miserable. When did you have your baby shower or when do you plan to have your baby shower?