Kim Kardashian West showed off her figure in new bikini pics on Instagram, proving age is just a number! A source tells ET that Kim is celebrating her 40th birthday with her family and close friends. A second source adds that the SKIMS mogul took everyone to an island on private planes to celebrate! This comes after Kim's mom Kris Jenner and sisters Kourtney Kardashian, Khloe Kardashian, Kendall Jenner and Kylie Jenner threw the ‘Keeping Up With the Kardashians’ star an over-the-top 40th birthday. Exclusives from #ETonline : https://www.youtube.com/playlist?list=PLQwITQ__CeH2Y_7g2xeiNDa0vQsROQQgv